SECTION 6: BIOCHEMISTRY
Section 6: Biochemistry
Resource management
Content
Elaboration
Biochemistry, preservation and
processing
Role of micro-organisms in the
development of flavours and textures
(Part 1)
Beneficial effects of micro-organisms
related to specific foodstuffs:
 cheese
 yoghurt
 alcoholic drinks
 bread
Role of micro-organisms in the development of flavours and
textures
The importance of enzymes to the food industry can be appreciated by
considering the wide range of their uses and applications, for example:

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enzymes
enzymes
enzymes
enzymes
in
in
in
in
cheese and milk production
the meat industry
the baking industry
the production of beverages and fruit juices.
Beneficial effects of micro-organisms in cheese production
Cheese manufacture is an ancient activity that has been modified and refined
over the centuries. Cheese making remained an essentially small -scale
activity until the application of scientific principles, around the early 20th
century, permitted large-scale manufacture. Today manufacture of the more
popular varieties is on a very large scale and cheese is an important export
commodity in the economies of the major producing countries such as Eire,
France, Australia and New Zealand. Cheese is made from milk by coagulating
the protein to form a curd and then maturing this with a starter culture of
lactic acid bacteria to produce a large number of differing cheeses. Varieties
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may be classified according to moisture content and according to the means
by which ripening is achieved.
The varying classes of cheese are as follows:
1.
Hard (26–50% moisture) can be further subdivided into:
 internally ripened, no added ripening micro -organisms, eg Parmesan,
Cheddar, double Gloucester
 internally ripened, added ripening bacteria, eg Emmental
 internally ripened, secondary surface ripening by mould, eg Blue
Cheshire.
2.
Semi-hard (42–52% moisture) can be further subdivided into:
 internally ripened, no added ripening micro -organisms, eg
Lancashire, Edam
 internally ripened, ripening mould added, eg Stilton, Roquef ort.
3.
Semi-soft (45–55% moisture) can be further subdivided into:
 surface ripened, ripening bacteria added, eg Limburger, Port Salut.
4.
Soft (48–80% moisture) can be further subdivided into:
 surface ripened, ripening mould added, eg Brie, Camembert
 unripened, eg Cottage, Coulommier.
5.
Others, eg brined varieties, whey cheese.
Technology
The basic technology for the manufacture of all types of cheese is similar ,
with relatively small changes in procedures during manufacture resulting in
perceived differences in the final cheese. The technology is well established
but has been subject to a considerable degree of refinement and automation.
Role of starter micro-organisms (enzymes) in the manufacture
of cheese
In modern practice, bacteria of the group commo nly referred to as lactic acid
bacteria (LAB) are added to milk to as starter cultures, their key role being
the production of lactic acid by fermentation of lactose. Lactic acid is
responsible for the fresh acidic flavour of unripened cheese and is of
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importance in the formation and texturing of the cheese . In addition, starters
cultures play other essential roles, eg:
 the production of volatile flavour compounds such as dracetyl and
aldhydes
 the synthesis of the proteoytic and lipolytic enzymes involved in the
ripening of cheese and the control of pathogenic organisms.
Starter cultures
The starter culture used in cheese making can be prepared in a number of
ways. Traditionally a liquid culture, called the bulk starter, was used in
cheese making. Direct vat innoculation cultures, which are concentrated
cultures in freeze dried or frozen form, are now widely used. The choice of
starter culture used in cheese making will to some extent determine the
flavour and texture properties of the curd.
Micro-organisms and enzymes in cheese manufacture
Micro-organisms are used in cheese making to:
1.
2.
3.
promote acid development during curd manufacture
confer distinct textural properties to the cheese
confer distinct flavour properties to the cheese.
1.
Acid production
Acid production during cheese making is essential in the formation of a
gel from the milk casein. The development of acid throughout the
cheese making process encourages the contraction of rennet curds on
heating and the expulsion of moisture from the che ese by syneresis.
2.
Textural properties
The extent of acid development influences the textural properties of the
cheese, and also provides the correct environmental conditions that
allow the formation of flavourful compounds in cheese manufacture.
Varying types of micro-organism are used to produce low levels of
carbon dioxide, thereby giving the desired textural characteristics in
some mould-ripened cheeses, eg moulds are used to assist in the
ripening of Camembert, Brie and Roquefort.
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3.
Flavour properties
Varying types of micro-organisms are used to produce distinct flavours,
eg the propionic bacteria used in the manufacture of Emmental and
Gruyere produce propionic acid and carbon dioxide. The propionic acid
contributes a distinct flavour character to the cheese, while the carbon
dioxide is essential for the development of ‘eyes’. In unripened cheese,
the lactic acid produced by the starters contributes to the sharp flavours
of the cheese. In cheese which is ripened, the lowering of the pH of the
curd will to some extent control the rate of enzymic reactions
responsible for flavour development, and ensure that the flavour
compounds formed are maintained in a stable condition.
The growth of spoilage and pathogenic bacteria is suppressed by
lowering of the pH during cheese manufacture.
Beneficial effects of micro-organisms in yoghurt manufacture
Yoghurt is made from milk that has been fermented by micro-organisms. In
the UK it is usually made from cows’ milk, but goats’ or ewes’ milk can also
be used. Yoghurt is eaten all over the world, and originates from west Asia
and eastern Europe.
Types of yoghurt
Yoghurt is divided into two main categories according to its consistency and
method of manufacture:
 set yoghurt
 stirred yoghurt (either thick or pouring consistency).
Composition
Yoghurt can be made from milk in any of the following forms:
 whole milk – minimum fat content 3.5% as recommended by the Food
Standards Committee in 1975
 semi-skimmed milk – minimum fat content 1–2%
 skimmed milk – minimum fat content 0.3% as recommended by the Food
Standards Committee 1975.
Concentrated skimmed milk is most often used in commercial yoghurt
manufacture. The Food Standards Committee also recommends that yoghurt
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should contain not less than 8.5% non-fat solids, which consist of casein and
whey proteins. The firmer the yoghurt, the more solids there are and the less
likely it is to separate. The milk used must conform to the same high
standards of hygiene and composition as liquid milk, and it must also be free
from the antibiotics that are given to cows to treat udder infections, as these
antibiotics affect the bacteria used in yoghurt production.
Bacteria culture
The taste and texture of yoghurt are brought about by carefully controlled
addition of a special harmless bacteria culture. The bacteria used belong to
the lactic acid bacteria group, which ferment the disaccharide sugar lactose in
milk. Under the right conditions of temperature, moisture and food they
produce lactic acid.
The two bacteria used are:
1.
2.
lactobacillus bulgaricus
streptococcus thermophillis.
During fermentation the milk proteins coagulate and the yoghurt sets. A
colourless volatile liquid called acetaldehyde is also produced. It is
acetaldehyde that is mainly responsible for the characteristic flavour of
yoghurt.
Commercial manufacture
The process outlined below is a general method used in the commercial
manufacture of stirred yoghurt but the method varies between manufacturers
to give them the opportunity to create their own disti nct product.
1.
2.
3.
4.
5.
6.
The milk is homogenised to give the finished yoghurt a smooth, creamy
texture. This also helps to prevent the final product separating.
The milk is then pasteurised at 85–95C for 15–30 minutes. This helps
to stabilise the proteins and results in a nearly sterile product.
The milk is then cooled to 40–43C, which is suitable for the
fermentation process to take place.
The two bacteria (the ‘starter’ culture) are added to the milk in equal
proportions, usually as 0.5–2% of the total finished product.
The culture is then incubated at 37–44C for 4–6 hours, during which
time fermentation takes place, the product becomes acidic, the flavours
develop and the proteins coagulate.
Once the level of acid reaches 0.8–1.8% the bacteria growth stops,
although the bacteria remain alive.
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7.
8.
The yoghurt is then cooled to 4.5C and held at this temperature during
storage and distribution to shops.
Additives may be included in the yoghurt, for example:
 vitamins A and D
 stabilisers, eg gelatine, agar and pectin, to prevent the yoghurt from
separating into curds and whey
 sucrose
 colour
 flavourings, eg strawberry, black cherry
 preservatives.
Additives are strictly controlled by legislation.
Storage of yoghurt
Yoghurt should be stored at 4.5C as at this temperature the bacteria grow
very slowly. After about 10 days they begin to affect the finished product as
the bacterial growth raises the acid content , which makes the product
unpalatable and it begins to separate. In fruit yoghurt, the yeast cells from the
added fruit ferment the sucrose and produce carbon dioxide gas and alcohol ,
which can be seen when the lid of the yoghurt container becomes raised, ie
‘blown’.
Yogurt products
It is possible to buy a range of yoghurt -based products, including:
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bio-yoghurts
yoghurt drinks
yoghurt ice cream
soya yoghurts.
Enzymes in the production of beverages and fruit juices
Micro-organisms play a part in the preparation and manufacture of beverages
and fruit juices in many ways, from the relatively uncontrolled activities in
the production of tea and coffee, through to the highly controlled action of
adding commercial enzymes found in the brewing and fruit juice industries.
Alcohol production using micro-organisms/enzymes (wine and beer)
‘Brewing’ is the term for hot water extraction of plant materials, thus making
coffee or tea is brewing. Brewing is a critical step in beer making and the
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entire process is called brewing, but this does not completely describe the
steps involved. Brewing of beer goes back 6000 years, and today’s practices
are similar to those used in earliest times. What has been gained is an
understanding of the principles of the biochemistry and microbiology
underlying the beer making process and a high degree of sanitation and
efficiency in the manufacturing practices.
Alcohol using micro-organisms/enzymes
The two most important industrial uses of yeast are in the production of
alcohol and in the making of bread.
The economic importance of yeast lies in its ability to break down
carbohydrate foods into alcohol and carbon dioxide. This process is known as
‘alcoholic fermentation’. Yeast contains a collection of enzymes, known as
zymase, which are responsible for the fermentation of sugars, such as
glucose, into ethanol and carbon dioxide.
Raw materials and manufacture
The principal raw materials of beer manufacture are water and hops, and
malted cereal grains, mainly barley. In many cases, rice, corn or other
unmalted grains are also added as a source of additional or ‘adjunct’
carbohydrate for the fermentation by Saccharomyces yeast into ethyl alcohol
and carbon dioxide. The hops are used to add the characteristic flavour of
most beers; additional carbon dioxide may be added to the amount naturally
produced by fermentation.
Malt
Malt is barley grain that has been germinated to the point where roots and
stems just begin to appear. The green malt is then gently dried to stop the
growth yet leave enzyme activity intact. Germination results in the activation
of enzymes that convert starches in the malted barley and in other cereal
grains into sugars, which can be easily fermented by the yeast during the
formation step. This is necessary because yeast cannot utilise the starch in the
cereal grains for the conversion to ethanol and carbon dioxide.
Hops
The flowers of the hop plant contain resins and essential oils that contribute
to a characteristic bitter flavour and pleasant odour to beer. Hops also contain
tannins, which add to the beer colour. Hops are added during brewing and
after the enzymes of the malt have converted the starch to sugar maltose.
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Hops also have mild preservative properties and add foam -holding capacity to
the beer. The main function of hops, however, is their role in flavour and
aroma.
Cereal adjuncts
Corn, rice and other cereals are used in beer making to provide supplemental
carbohydrates, principally starch, for conversion to sugar for subsequent
fermentation. Without these adjunct cereals, the limiting nutritional factor for
yeast in fermentation would be protein. This means that carbohydrate would
remain after fermentation and produce a heavier type beer. In some cases, this
is desirable, but most breweries prefer lighter -type beers.
Wine
The making of wine by fermenting grapes has a long tradition and goes back
to at least 4000 BC.
Wine varieties
The varieties and names given to wine are legion and reflect the region of
origin, varieties of grape used in the manufacture and certain properties such
as degree of sweetness, colour, alcohol content and effervescence.
Sweetness and alcohol content
The sweetness and alcohol content of wines are interrelated because
fermentation converts grape sugars to ethanol. As more alcohol is produced,
the sweetness decreases. When virtually all of the sugar is fermented, the
wine is without sweetness and is said to be ‘dry’. Dry wines contain all the
alcohol that the specific grape is capable of yielding under the conditions of
fermentation. This generally is 12–14% alcohol by volume.
The relationship between disappearance of sweetness and increase in alcohol
content cannot be used to characterise wines, however, because both alcohol
content and the sweetness of finished wines can be further and independently
adjusted. The terms ‘natural’ and ‘fortified’ also have been used in relation t o
alcohol content. Depending on the sugar content of the grapes, the
characteristics of the yeast culture and the fermentation practices employed,
natural fermentation generally yields an alcohol concentration of less than
16% by volume even if more sugars are added. This is because the amount of
alcohol is toxic to the yeast and it stops fermentation. The wine must still be
pasteurised after bottling to ensure against growth of unwanted micro organisms.
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The term ‘light wine’ is used to describe a wine having an alcohol content
from about 5 to 10% (the term ‘light’ has nothing to do with colour).
Fortified wines are those that have received additional distilled spirits to
bring their alcohol content up to 17–21% by volume. They are less perishable
and may be stable without pasteurisation.
Fermentation
As grapes mature, the wine yeast Saccharomyces euipsoideus naturally
accumulates on the skins. When the crushed grapes of filtered juice are held
at a temperature of about 27C, the juice proceeds to ferment, yielding
essentially equal quantities of ethyl alcohol and carbon dioxide , and traces of
flavour compounds.
Wine yeast is relatively resistant to sulphur dioxide and so this agent
commonly is added to the grapes to help control undesirable microorganisms, particularly bacteria. Sulphur dioxide is also effective in
inhibiting the browning enzymes of the grapes and providing reducing
conditions by reacting with oxygen. Fermentation causes a rise in
temperature, and so cooling is required to prevent yeast i nactivation.
Fermentation under conditions of limited exposure to air may continue until
the sugar is entirely consumed, when it stops naturally, or fermentation may
be interrupted prior to this. At around 27C, fermentation may last for some
10 days, depending on the type of wine.
Bread production using micro-organisms/enzymes
The two most important industrial uses of yeast are in bread making and for
the production of alcohol.
Yeast contains a number of enzymes, known as zymase, which are
responsible for the fermentation of sugars, such as glucose, into ethanol and
carbon dioxide. This process is known as ‘alcoholic fermentation’.
Yeasts are simple, single-celled fungi. There are two main forms used in the
making of bread:
 Fresh yeast. This is sometimes called ‘live’ or ‘fresh’ yeast, which is quick
and easy to use but can be difficult to obtain. It should be stored in a
refrigerator to prevent multiplication in advance of use.
 Dried yeast. This is sometimes called ‘dried’ or ‘dehydrated’ yeast. It i s
very useful as it has a shelf life of 1 year.
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Bread making
Several ingredients are required in the fermentation process, namely:
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water
yeast
salt
sugar
flour
fat
The water should to be warm, ie blood temperature, approximately 32 C, to
encourage the yeast to ferment. At a temperature of 43 C, yeast cells are
inactivated and at 54C they are killed. It is therefore very important that the
correct temperature of water is used for optimum results.
The yeast uses a small amount of sugar as a starter t o ferment and produce
carbon dioxide and alcohol.
Salt is added to the dough to give flavour. The amount of salt used is a
delicate balance because too much salt can inhibit the yeast whilst too little
can cause the dough to be sticky and unmanageable.
Fat is used in the dough to help improve the bread’s keeping qualities.
‘Hard’ flour is used, ie flour containing a high amount of gluten.
When the flour is kneaded with water, the two proteins present in flour,
gliadin and glutenin, become hydrated and form an elastic complex called
‘gluten’. The manufacture of bread is possible due this protein complex.
The gas produced stretches the gluten in the dough , producing little bubbles
which become trapped, forming the characteristic framework of the loaf.
When the dough is baked, the increase in temperature causes the carbon
dioxide bubbles to expand within the dough, thereby causing a further rise in
the volume of the bread.
The heating also causes the gluten to ‘set’, turning the dough into bread.
During baking the expansion of the carbon dioxide causes the bread to rise
rapidly and the alcohol produced during the fermentation process is driven
off.
At a temperature of approximately 54C, the yeast is inactivated.
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The action of heat and steam on the outside of the bread forms dextrin, which
converts to caramel, giving the crust its brown colour.
Chorleywood bread-making process
This is a well-known commercial method of making bread used by large and
small companies alike. It is fundamentally the same process as for homemade
bread but it is much faster as the time -consuming fermentation stage of the
process is replaced by high-speed mixing.
Other types of bread
There is a huge variety of different breads on the market, but the basic
fundamentals apply to all. Unleavened bread is made without yeast and is
basically a mixture of water, flour and flavourings only. Breads such as
ciabatta and foccaccia have olive oil added. Croissants and pastries may have
eggs, butter and other fats added, and there may be varying quantities of
sugar in sweeter breads such as Danish pastries.
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Resource management
Content
Elaboration
Biochemistry, preservation and
processing
Adverse effects of micro-organisms and
enzymes in the development of flavours
and textures in food
Physical and chemical changes in
foodstuffs after preservation, affecting
structure, texture, colour and nutritive
value
(Part 2)
Adverse effects of micro-organisms and enzymes in the
development of flavours and textures in food
Food poisoning is an unpleasant illness that can occur after eating
contaminated foods that may appear harmless – the colour, taste and
appearance look normal.
If food spoilage occurs, the colour, taste and appearance of the food change
so the food should not be eaten.
The micro-organisms mainly responsible for food spoilage are moulds,
bacteria and yeasts.
The types of food poisoning are:
 chemical
 biological
 bacterial.
Chemical
This type of food poisoning should not be common if all hygiene regulations
are adhered to.
Chemical food poisoning takes place if food is contaminated by substances
added to food during agricultural production, storage or manufacture, for
example:
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

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residues of drugs given to animals
residues of pesticides or fertilisers
misuse of a chemical during agricultural production
cleaning chemicals used for cleaning machinery during food production
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 contaminants leeching into food from packaging.
Biological
This type of food poisoning is caused by eating foods containing naturally
occurring toxins.
A few natural toxins are thought to contribute to food poisoning. The main
ones are as follows:
1.
Scombrotoxin found in fish (eg certain types of oily fish like mackerel
and tuna). This type of poisoning is caused by heat -stable toxins, which
are freed by the action of bacteria on fish protein during spoilage. The
toxin is produced by bacterial action but is not itself a bacterial toxin.
Symptoms include flushing, sweating and sometimes nausea and
diarrhoea.
2.
Raw red kidney beans contain a toxic substance called haemagglutinin,
which causes the red blood cells to stick together. Raw kidney beans
must be boiled for 10 minutes to kill this toxin. Tinned kidney beans are
safe to eat as they have been heated during processing.
3.
Solanine is found in potatoes and has a green appearance. In high
enough quantities it will cause headache, vomiting and diarrhoea and
can even be fatal. However, the levels of solanine in potatoes are rarely
sufficient to cause illness. Green potatoes should not be eaten.
4.
Paralytic shellfish poisoning. This is rare but can result in serious and
sometimes fatal food poisoning. It is caused by eating raw mussels or
oysters that have fed on a certain type of plankton.
5.
Some fungi produce toxic chemicals called mycotoxins. The dea th cap
mushroom (the amanita variety) contains this poisonous toxin and
eating this variety will cause liver damage and even death. Th is type of
mushroom is similar to the edible variety and could easily be picked
and eaten by mistake.
6.
Moulds also grow on many foods that will not support bacterial growth
because fungi are more tolerant of low water and low pH than bacteria.
These include nuts, bread, jam and cheese. These mouldy foods could
be potentially dangerous and should always be thrown out.
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Bacterial (bacteria or their spores and toxins)
Bacterial food poisoning is the most common type of food poisoning and
takes place when food is contaminated by pathogenic bacteria.
Spores
 Some bacteria are able to produce spores.
 Spores are bacteria in a resting state and they do not multiply.
 When the spores return to favourable conditions, the y release the
bacterium, which will then grow and multiply.
 Spores can be very resistant to heat. High temperatures of above 100 °C for
long periods of time are often needed to destroy spores.
 Spores can also resist a high concentration of chemicals.
Toxins
 Some pathogenic bacteria produce a toxin or poison in the food that is
difficult to destroy by normal cooking processes.
Conditions required for the growth of bacteria
1.
Warmth
 The best temperature for the growth of bacteria is 37 °C – body
temperature.
 The temperature range of 5–63°C is often referred to as ‘the danger
zone’. Foods should be kept below or above these temperatures
whenever possible.
 Ensure that food is thoroughly cooked to core temperatures of 75 °C
or above.
 Reheat food to 82°C. Small numbers of bacteria may have survived
the original cooking and continue to multiply. By increasing the
temperature, these bacteria will be destroyed.
 At room temperatures of 20–50°C bacteria will multiply rapidly.
 Most bacteria will multiply very slowly in a refrigerator (1 –4°C).
 No bacteria will multiply in frozen food ( –18°C) but many will
survive and reproduce on thawing.
2.
Food
 Like all living cells bacteria need food to grow.
 Some food are high-risk foods because:
– bacteria grow easily on these foods – these foods are usually high
in protein and moisture
– they can be eaten without further cooking, which would normally
destroy the bacteria
– they require refrigerated storage.
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 Examples of high-risk foods are:
– all cooked meats and poultry
– cooked meat products, eg stew, gravies, sauces, stock and soups
– shellfish and other sea food
– milk, cream, artificial cream, custards and dairy produce
– cooked eggs and products made from egg, eg raw eggs in
mayonnaise
– cooked rice.
 Other foods that do not normally support the growth of bacteria are
known as low-risk foods.
 Examples of low-risk foods are those which are high in:
– salt
– sugar
– acid.
 This is why food preservation methods such as salting, jam making,
pickling or keeping food in syrup are successful.
3.
Moisture
 Like all living cells, bacteria need moisture to grow.
 Bacteria prefer a high water content but many foods contain
sufficient moisture for growth.
 Once dried foods such as milk powder and dried egg have water or
milk added then any bacteria present will start to multiply.
 It is essential to use this food as soon as possible after adding the
water.
4.
Time
 Given the correct conditions of food, moistu re and warmth some
bacteria can divide into two every 12–20 minutes. This process is
called binary fission.
 A few bacteria, given sufficient time, can multiply quickly to
produce enough to cause food poisoning.
 It is essential that high-risk foods are in the danger zone (5–63°C)
for as short a time as possible.
5.
Oxygen (aerobes and anaerobes)
 Most bacteria require oxygen to grow. These are called aerobic
bacteria.
 Some bacteria do not require oxygen to grow. These are called
anaerobic bacteria.
6.
pH levels
 Acidity is measured using the pH scale, which has 14 points.
 pH 7 is neutral, that is neither acid or alkaline.
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 Most pathogenic bacteria cannot grow in an acid environment of pH
4.7 or less, for example in the pickling method of preservation.
Main food-poisoning bacteria
(a)
Food poisoning caused by bacteria such as:

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salmonella
staphylococcus aureus
clostridium perfringens
bacillus cereus.
In this type of food poisoning a large number of bacteria are usually involved
and this normally requires them to multiply within the food.
(b)
Food poisoning caused by food-borne diseases such as:
 campylobacter enteritis
 listeria
 E. coli 0157.
Food-borne diseases are usually food related. Only small numbers of these
bacteria are required to cause the illness and t hey do not need to multiply
within the food. The bacteria responsible are usually found in the intestines
of humans or animals.
(a) Food poisoning caused by bacteria
1.
Salmonella
 Salmonella are aerobic bacteria that do not form spores.
 They grow at temperatures between 6 and 46°C. The best
temperature for growth is 37°C.
 They are killed rapidly at 75°C.
 This bacteria can grow aerobically (with oxygen) or anaerobically
(without oxygen).
 Symptoms include fever, headache, abdominal pain, diarrhoea and
vomiting. Symptoms may last from 1 to 7 days.
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Sources of salmonella
Intensive farming methods and slaughtering practices mean that raw meat,
poultry and eggs could be potential sources of salmonella.
Chickens reared under battery conditions are likel y to be infected with
salmonella more than free-range hens. This is due to the fact that the hens are
kept close together and cross-infection occurs between birds.
Eggs and products containing raw eggs (eg mayonnaise) or only lightly
cooked eggs may contain salmonella. Eggs may have salmonella on the shell
and inside the egg. It is advised that all eggs should be well cooked.
Rats, mice, domestic pets and birds may carry the bacteria in their intestines,
on their fur/feathers and on their feet.
Food handlers carry this bacteria in their intestines so could contaminate the
food if they do not washed their hands after visiting the toilet.
Prevention
Personal hygiene
Wash hands before and after handling food, especially raw meat, poultry and
eggs.
Kitchen hygiene
Use different surfaces and equipment such as knives and chopping boards for
preparing raw and cooked food to prevent cross -contamination.
Clean all surfaces, equipment and tools thoroughly before and after use to
prevent cross-contamination from raw to cooked foods.
Correct storage of foods
High-risk foods should be stored covered under refrigeration at 4 °C or less.
Cooked and uncooked meats should be stored separately if possible or raw
meats or poultry should be stored below cooked foods to prevent any drips of
blood from raw meats contaminating the other foods.
Thawing food
Thaw frozen meat and poultry thoroughly before cooking, preferably by
thawing in the refrigerator overnight. Frozen meat and poultry should not be
left to defrost at room temperature as bacteria will multiply.
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Cooking/reheating thoroughly
Cook food thoroughly so that the temperature (75°C) at the centre of the food
is high enough to kill bacteria. Eggs in particular should be thoroughly
cooked as should meat joints, chicken and turkey.
Food must be reheated to 82°C.
2.
Staphylococcus aureus
 This bacteria multiplies in food stored between 10 and 40°C,
producing a toxin. When food is swallowed this toxin irritates the
stomach lining, causing vomiting.
 Does not multiply below 5°C.
 This bacteria is killed by heat (1–2 minutes in boiling water) but the
toxin it produces is more resistant to heat and can withstand up to 30
minutes in boiling water.
 Lightly cooked food will contain no living bacteria but may contain
active toxin, which will cause food poisoning.
 Symptoms include vomiting, abdominal pain, diarrhoea, exhaustion
and sub normal temperatures. Symptoms last no more than 24 hours.
Sources of staphylococcus aureus
 Humans, in the warm, damp conditions of the nose, th roat, pores and hair
follicles of the skin.
 In boils, styes and septic cuts. Can be transferred to food via the hands.
 Food can be contaminated after cooking when eaten cold or only mildly
reheated such as sliced cold meat, cooked poultry, stuffed rolled j oints of
meat not cooked in the centre, cream dishes, custards.
 Can grow in a higher salt concentration than other food poisoning bacteria
and so can be found in ham.
Prevention
Personal hygiene
Wash hands before and after handling food. No coughing or sneezing over
food. Cover cuts and sores with a waterproof dressing. Handle food as little
as possible and use tongs for lifting.
Kitchen hygiene
Maintain a high standard of kitchen hygiene, eg chopping boards, cutting and
mincing machines and cloths must be cleaned thoroughly after use.
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Thorough cooking/reheating
Rapid cooking of high-risk foods to prevent spreading of this bacteria
produces a toxin in food that is difficult to destroy by normal cooking
temperature. Reheat foods once only to 82°C to destroy the bacteria.
Correct storage of foods
Store high-risk food in a refrigerator at 4°C or below.
3.
Clostridium perfringens
 This is an anaerobic bacteria that grows best in the absence of
oxygen.
 The best temperature for growth is between 43 and 47 °C.
 Spores of this bacteria will pass out with the faeces of animals and
humans into the soil and sewage systems. Water and vegetation carry
the infection back into the animal kingdom and so into food
production systems.
 Can survive cooking by forming spores.
 Reheating should be carefully done because of the spores that may
be formed.
 The anaerobic nature of this bacteria allows it to multiply in the
internal cavities of meat and poultry where oxygen has been driven
by the heat of cooking so care must be taken when cooking food in
bulk.
 Symptoms include abdominal pains and diarrhoea. Rarely vomiting.
Symptoms last 1–2 days.
Sources of clostridium perfringens
 Present in animal and human intestines so will be present in animal and
human excreta.
 Soil and vegetables covered in soil or dust.
 Raw meat and poultry.
 Flies, cockroaches and bluebottles.
Prevention
Personal hygiene
Wash hands after handling raw meat and unwashed vegetables. Wash hands
thoroughly after visiting the toilet.
Kitchen hygiene
Use different surfaces, boards and equipment for raw and cooked foods.
Remove soil regularly from vegetable stores and preparation areas. Scrub
vegetables before peeling.
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Correct storage of food
Separate raw and high-risk foods. Cool cooked foods quickly and refrigerate
them immediately at 4°C or less – large volumes of meat should be divided
into smaller portions to cool more quickly.
Reheating
Reheat quickly and thoroughly to 82°C and serve immediately. Never reheat
meat products more than once.
4.
Bacillus cereus





This is an aerobic bacteria that grows best with oxygen.
The best temperature for growth is between 35 and 38 °C.
Forms spores when conditions are unfavourable for growth.
Spores will survive most cooking processes.
If food is left in a warm place or not cooked quickly then spores
germinate, producing vegetative bacteria, which in turn multiply and
produce a very heat resistant toxin.
 If food is then reheated quickly or insufficiently the heat is unlikely
to destroy the toxin. When the food is eaten th e toxin irritates the
stomach lining, which causes vomiting.
 Symptoms – there are two types of illness:
– Vomiting type.
This begins 1–6 hours after eating contaminated food and does not
last more than 24 hours. It is thought that an enzyme in saliva
starts the digestion of starch in the mouth and so releases the
toxins, which are vomited out before reaching the intestines.
– Diarrhoea type.
This begins 8–16 hours after eating contaminated food. Symptoms
include diarrhoea, abdominal pain but rarely vomiting . This type
is less common and lasts less than 24 hours.
Sources of bacillus cereus

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Soil and dust.
Spices.
Vegetables.
Dairy products.
Eggs.
Cereals, particularly rice and cornflour.
Rice dishes, cornflour sauces and milk pudding.
Cooked rice dishes.
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Prevention
Kitchen hygiene
High standards of kitchen hygiene must be maintained, eg clean surfaces and
equipment. Check cereal dust is removed from storage and preparation areas
to avoid contamination.
Soil and dust
Ensure vegetables are washed before using. Ensure soil from vegetables left
lying around in storage areas does not contaminate surfaces.
Pre-cooked rice
Avoid preparing rice in advance because if the rice is left in a warm kitchen,
bacteria can multiply. Reheating during flash frying, as in fried rice, must be
thorough or else bacteria will not be destroyed. Cool rice immediately after
cooking, then refrigerate. Cook smaller amounts of rice to avoid the need to
store it. Ideally left over rice should be thrown out. Avoid reheating rice but
if necessary reheat thoroughly and serve at once. Throw out cooked rice after
24 hours.
(b) Food poisoning caused by food-borne diseases
1.
Campylobacter enteritis
 This bacteria grows under partial anaerobic conditions.
 The best temperature for growth is 43°C.
 Symptoms include headaches, dizziness, backache, abdominal pain
and diarrhoea. The illness can last 2 to 3 days.
Sources
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Farm animals such as cows, sheep and chicken s.
Domestic animals such as cats and dogs.
Infection can be spread from animal to person and from person to person.
Raw and undercooked chicken.
Raw, unpasteurised milk.
Untreated natural water.
Cross-contamination from raw to cooked foods, eg meat and poultry.
Prevention
Personal hygiene
Wash hands before and after handling food, e specially raw meat and poultry.
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Kitchen hygiene
Clean all surfaces, equipment and tools thoroughly before and after use to
prevent cross-contamination. Do not allow domestic pets into areas where
food is prepared.
Correct storage of food
High-risk foods should be stored in a refrigerator at temperatures of 4 °C or
below as the bacteria find it difficult to multiply.
Cooking thoroughly
All chicken must be cooked thoroughly as campylobacter is destroyed by
heat.
Separation of raw and cooked foods
Display, store and prepare raw and cooked foods separately to prevent
contamination between raw and cooked foods , eg meat and poultry.
2.
Listeria
 Vacuum packing and modified atmosphere packing, in which the
level of oxygen is decreased and the level of carbon dioxide is
increased, help to prevent the growth of listeria.
 Strict temperature control must be enforced during the distribution
and storage of ready-to-eat products.
 At-risk groups should avoid high-risk foods. Pregnant women should
avoid patés and soft cheese as they may contain listeria, which can
damage the foetus, cause a miscarriage, stillbirth or illness in the
newborn baby. Elderly people and people with reduced immunity due
to illness are also at-risk groups.
 Symptoms:
– Infection with listeria causes listeriosis. Bacteria get into the
bloodstream and multiply.
– In mild cases the person will feel shivery and feverish.
– In high-risk groups, listeria can cause meningitis, severe aches
and pains, fever, confusion, septicaemia and pneumonia.
Sources
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Soft-ripened cheeses such as Brie and Camembert.
Paté, salami and continental sausages.
Cook-chill meals.
Raw and cooked meats, ready-to-eat chicken.
Fish and seafood.
Coleslaw and pre-packed salads.
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Prevention
Personal hygiene
Listeria is found in human excreta and soil, therefore food handlers should
follow strict personal hygiene rules when handling and preparing high -risk
foods,
Correct storage of food
Refrigerate below 4°C. Although listeria still can multiply at this temperature
or lower, the growth should be slower. Listeria may even grow very slowly at
0°C. Observe use-by dates. Bacteria need time to multiply, therefore highrisk foods should be thrown out after the use -by date.
Wash salads, fruit and vegetables
Listeria is found in soil, therefore traces may occur in plant foods. If these
foods are eaten raw listeria will still be present.
Cooking thoroughly
Cook above the core temperature of 75°C for at least 2 minutes. Most listeria
will be destroyed at this temperature. Ensure that food cooked in the
microwave is not unevenly heated as listeria could survive in cooler parts of
the food.
Reheating thoroughly
Reheat to 82°C. Small numbers of bacteria may have survived the original
cooking and continue to multiply. By increasing the tempera ture, these
bacteria will be destroyed.
3.
E. coli 0157
 This bacteria grows aerobically and anaerobically.
 The best temperature for growth is 37°C but it is readily killed at
temperatures above 55°C.
 Symptoms:
– Illness can last 1 to 5 days or can be life threatening.
– Abdominal pain, fever, diarrhoea, sometimes vomiting.
– In babies the acute diarrhoea and dehydration can be fatal.
– E. coli 0157 can cause kidney failure and, particularly in children,
can lead to temporary or permanent kidney damage and anaemia.
– Toxins can be released that destroy gut and kidney cells, which
can be fatal.
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Sources
 Raw foods of animal origin, eg meat and poultry.
 Can be passed to cooked food by cross -contamination from hands, surfaces

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and equipment.
Mincing meat can spread bacteria throughout the meat.
Undercooked meats, especially hamburgers.
Incorrectly pasteurised milk and milk products.
Water in foreign countries.
Prevention
Personal hygiene
Wash hands before and after handling food, especially raw meat and poult ry.
Kitchen hygiene
Clean all surfaces, equipment and tools thoroughly before and after use to
eliminate all bacteria present.
Good food hygiene practices
Any business dealing with food should rigorously apply the hazard analysis
critical control point system.
Correct storage of food
Meat should be stored in a refrigerator at temperatures of 4°C or below as
bacteria find it difficult to multiply at this temperature.
Separation of raw and cooked foods
Display, store and prepare raw and cooked meat/foods separately to prevent
contamination between raw and cooked foods.
Cooking thoroughly
All meat and meat products must be cooked thoroughly as E. coli is destroyed
by heat. Use a metal temperature probe to ensure joints are cooked
thoroughly.
Serve food very hot
Above 82°C most bacteria die, therefore if food is served at that temperature
the bacteria will not have time to multiply.
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Physical and chemical changes in foodstuffs after preservation ,
affecting structure, texture, colour and nutritive value
The main aims when preserving food long term are to prevent:
 microbial growth
 cellular breakdown caused by enzymes contained within the food.
Preservation also aims to retain as many qualities of the fresh food as
possible, such as colour, flavour, texture and nutritional value.
(a)
Removal of moisture
Dehydrating
This is the oldest and simplest method of preserving food. Dehydration
involves the removal of moisture from the food by applying heat , usually in
the presence of a controlled flow of air. Micro-organisms and enzymes, like
all living things, cannot grow and multiply without moisture. Water is drawn
out from the cells and this concentrates natural salts or sugars , which
preserves the food.
It is important that the temperature used should not b e too high, since this
will cause undesirable changes in the food and could result in the outside of
the food becoming brittle and hard whilst moisture is trapped in the centre of
the food and is unable to ‘escape’ through the food by diffusion.
Removing water from food also reduces the bulk and weight of the product.
The food will stay dehydrated until the water is put back into the product
(rehydrated). Once water is added back into the food, micro -organisms will
start to grow and reproduce again. Dried food must therefore be stored in a
cool, dry place.
The effects of dehydration
 Colour – The colour of the food may change completely, darkening as it
becomes concentrated as the food dries, eg green grapes turn to brown
sultanas or currants.
 Texture – Food will become brittle (herbs) or hard (dried pulses) or it may
crumble (coffee granules).
 Appearance – Food may wrinkle, shrink in size and become lighter in
weight, eg dried plums become prunes, vegetables in dried soups.
 Flavour – Food becomes sweeter or more salty as a result of the removal
of the moisture.
 Nutritional value – Some vitamin C and vitamin B1 (thiamin) may be lost.
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Freeze drying (accelerated freeze-drying, AFD)
The food is first of all frozen and then subjected to a mild heating process in
a vacuum cabinet. The ice crystals formed during the freezing stage change
directly from ice to water vapour.
This method of drying causes little damage to the food because the ice is
driven off as water vapour, and it is therefore a useful method for heatsensitive foods. The size and shape of the original food is retained. Since
little heat is used, there is little heat damage and no discolouration of the
product colour – sometimes colour is improved, offering a more appealing
product for consumers.
Flavour is retained through the process and so taste is improved. Sensitive
nutrients, such as the water-soluble vitamins, remain unharmed or suffer just
a minimal loss.
A wide variety of products can be freeze -dried, including meat, vegetables,
fruits, soups, dried milk and coffee.
(b)
Use of temperature
(i)
Heat
Heat treatment is the most effective method of preserving foods. Most
bacteria, yeasts, moulds and enzymes are destroyed by heating at100 °C.
The main methods of heat treatment are as follow s:
Pasteurisation
This process is commonly used for milk. In pasteuri sation, the milk is heated
to at least 72°C for 15 seconds to kill harmful bacteria. After this it is rapidly
cooled to less than 10°C. This process does not affect the appearance or
flavour of the product. There is a decrease in vitamin C and thiamine.
Pasteurisation is used for other food items such as milk products, fruit juices,
vegetable juices and liquid egg for bakery products.
Ultra heat treatment
Ultra heat treatment is a sterilising process in which foods are rapidly heated
to about 135–140C and held at that temperature for a few seconds to kill any
bacteria present.
The product is then rapidly cooled and packed in pre -sterilised containers. An
airtight seal prevents recontamination until the container is opened.
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Examples are long-life milk and fruit juices. These should keep for at least 3
months at room temperature.
However, the high temperatures achieved in the process lead to changes in the
natural flavours, appearance and smell of the items, which may not be
agreeable to consumers.
The losses of vitamin C and folic acid are similar to those which occur during
pasteurisation, for example of milk. However, some fruit juices are fortified
with vitamins to make up for the loss.
Sterilisation
Sterilised milk has been homogenised, filtered and heat -treated to at least
100C. This ensures that it remains in good condition for several weeks. The
process does cause a change in flavour. The colour of the milk is changed due
to the caramelisation of sugar in the milk and to the Maillard browning
reaction between the sugar and the amino acids. The vitamin content is
reduced, with vitamin C and thiamine being most affected.
Canning
A simple explanation of canning is that the foo d is sealed in a can, which is
then heated to such a temperature that all harmful bacteria and spores are
destroyed and then it is cooled.
The conditions involved in canning – time and temperature – are carefully
controlled as over-processing has an adverse effect on the quality of the
product.
There are variations on the standard canning process depending on the food.
Aseptic canning – where the product and the containers are sterilised
separately, then filled and sealed – is used mainly for liquid foods that are
heat sensitive. These could possibly be overcooked by the standard canning
process, eg custards, with resultant changes to flavour and colour along with
a reduction in nutrients.
Some nutrient loss occurs during canning, in particular vitamin C and
thiamine. However, vegetables and fruit are canned within a few hours of
being picked so even after canning the total loss of vitamin C may be less
than in fresh vegetables bought in a semi -fresh state and cooked at home.
(ii)
Cold
The main method of preservation involving cold temperature is freezing.
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Freezing
Freezing is the reduction of temperature in a food to the point where not only
does microbial activity stop, but the natural decay and deterioration of the
food by enzymes is halted for quite a length of time.
When a food is frozen, ice crystals are formed in it. The speed at which food
is frozen is important. If food is frozen quickly, small ice crystals will form ,
reducing the damage to the structure and texture of the food. When food is
frozen slowly, large uneven ice crystals are formed , which break through the
cells on thawing and affect the flavour, texture and nutritive value.
Frozen foods bear a close resemblance to the original fresh food. The
nutritive value of the food is not usually affected by the freezing process. In
the case of frozen fruit and vegetables the vitamin C content may be higher
than that of fresh as vitamin C content will be lost during transport and
storage. After picking, the fruit and vegetables are frozen quickly, after
blanching.
Blanching inactivates enzymes that may affect the colour and stability of the
food, particularly fruit and vegetables.
Foods containing fat dispersed in a colloidal form (an emulsion) may not
freeze successfully because during freezing as the water is solidified it causes
an increase in the concentration of the salt in the food , which may cause
irreversible changes in the colloidal structure.
Before freezing, ascorbic acid, which reduces the browning in some fruits and
vegetables, or antioxidants, which prevent any undesirable changes in any fat
present, may be added to the food.
Frozen foods remain in good condition for a longer period of time as micro organisms are dormant at these very low temperatures.
(c)
Acidity
Some acids are used as a preservative, for example vinegar, citric acid, lactic
acid and tartaric acid.
The acidity of a substance is measured by its pH value on a scale of 1 to 14.
Substances that have a pH of 1–6 are acidic, 1 being the most acidic. Most
micro-organisms cannot survive in acidic pH so food is preserved.
The acids that are used for preserving, such as vinegar for pickling, are
usually fairly strong. They usually have a pH of 2 –3 and so are suitable for
preserving less acid foods, eg pickled onions.
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Other preserves may use a mixture of acid, sugar and salt in their product, eg
chutneys.
The strength of an acid used to preserve food has to be adjusted according to
the type of micro-organism that would normally contaminate the food, eg
some moulds grow at pH 2 and yeasts grow at pH 4–4.5.
If the pH is low or acid a sour taste will be noticeable and will affect the taste
of the food product. A bitter taste will be noticeable if the pH is high or
alkaline.
(d)
Sugar
Sugar is added to food for a variety of reasons. It is:
– a preservative
– a sweetener
– an energy provider.
Sugar must be used in large quantities to act as a preservative, eg in jam
making.
Micro-organisms cannot grow in strong sugar solutions – a concentration of
60% sugar is therefore recommended.
Sugar is also used to preserve certain fruits and fruit peels by crystallisation.
The large amount of water present in the fruit is exchanged for the strong
sugar syrup when the fruit is allowed to soak in a concentrated sugar solut ion.
Sugar can also be a preservative when used in cakes and biscuits. Sugar helps
these products to stay moist, which keeps them in good condition for longer
and gives a longer shelf life.
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Resource management
Content
Elaboration
Biochemistry, preservation and
processing
Food additives:
 preservatives
 antioxidants
 emulsifiers
 sweeteners
 improvers
Specific commercial additives:
 anti-foaming agents
 colours
 bleaches
 flavour enhancers
 nutritional additives
The benefits of additives and safeguards
regarding their use
1.
Food additives
Additives are natural or synthetic substances that are added to foods to serve
particular purposes. The legal definition of an additive from the Food
Labelling Regulations 1984 is ‘any substance not commonly regarded or u sed
as a food, which is added to or used in or on food at any stage to affect its
keeping qualities, texture, consistency, appearance, taste, odour, alkalinity or
acidity or to serve any other technological function related to food.’
Additives must serve one or more of the following functions:




maintain the nutritional quality of food
improve the keeping quality of food
make food attractive to the consumer
provide essential aids in food processing.
Additives may be the following:
1.
Natural substances that have been produced biologically and have
been extracted from natural sources, eg lecithin , which is used as an
emulsifier in mayonnaise and sauces.
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2.
Synthetic compounds that are ‘nature identical’. These are synthesised
either chemically or biologically to match naturally occurring
counterparts, eg ascorbic acid (vitamin C) , which is used as an
antioxidant and can be produced synthetically.
3.
Artificial compounds that are synthesised chemically and have no
naturally occurring counterpart, eg one additive use d as a flour
improver has to be synthesised by chemical methods.
The benefits of additives
Food additives carry both benefits and risks for the consumer.
Additives are not new, they are an extension of traditional techniques, eg the
use of salt for preserving and the use of sodium nitrite for preserving and
curing hams.
Without additives it would be difficult to provide food in the enormous
quantities required today. Shelf life would not be as good, products would not
be as attractive and they would be dearer. Today’s consumer does not shop
for food every day and expects food to be reasonably priced, nutritious,
attractive, palatable and safe. It is the relationship between food additives and
safety that is the centre of current debate.
Food manufactures can only use additives that have been tested and found to
be safe. Legally, manufacturers are forbidden to add substances to food that
may injure health. However, testing of food additives may only take place in
animals and on an individual basis. The exact consequences of eating
combinations of additives by humans are not known. It is fair to say that
some additives may present a health problem but only to a small percentage
of the population.
Manufacturers are finding that they have to justify the pr esence of additives
and demonstrate a useful role and many are redesigning their products to
reduce or even omit additives. The fact that additives are not present in a
food is being used as a positive advertising feature. A statement on a label
that the product is free from artificial colourings means just that, and it will
probably contain natural colourings, preservatives, flavourings, etc depending
on the actual product. Consumers must read the labels carefully as some food
manufacturers may ‘play’ with words to give a false impression.
It is important that the risks of possible ill -effects from the presence of
chemicals in foods should be negligible compared with the benefits which
ensue, and the food additives approved for use in the UK perform useful
functions without harming the vast majority of consumers.
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Each additive should be considered on its merits
The use of synthetic colours is particularly difficult to justify. The risks,
though small, are thought by many people to outweigh substantially t he
dubious cosmetic benefits of the additives.
Additives are sometimes used to give manufactured foods properties
associated with the presence of traditional ingredients. Emulsifying agents
used to decrease the amount of fat needed in the manufacture of cakes and
bread come into this category. Although these reduce the amount of fat
required to produce familiar physical properties in cake, they do not, of
course, fulfil its nutritional functions. The amount of fat lost in this way,
when considered in terms of an individual, is not large, but for someone
living on a barely adequate diet it may not be insignificant. Most people,
however, eat too much fat and a reduction in intake would be beneficial.
Synthetic cream and meringues are often made from cellulo se derivatives,
which have absolutely no nutritive value. The use of colouring matter in
cakes to give an impression of richness is also open to criticism. There are
numerous other examples of the use of additives which contribute nothing to
the nourishment of the consumer. The more luxurious classes of foodstuffs
lend themselves particularly well to such sophistication and it may be argued
that these are not, in any case, eaten primarily for their nutritive value.
The use of nitrates in meat products to prevent food poisoning by Clostridium
botulinum is well established. There is the risk, however, that the nitrites in
food are partly converted into a substance that is known to produce cancer in
animals. At the low levels permitted in specified foods nitrites are now not
known to have caused any harm to any human being. Nevertheless, the risk
remains and it is a matter of judgement whether the risk is considered to be
justified in the light of the known benefits.
The overall benefits of food additives can be summarised as follows:
 Foods have a longer shelf life and so the consumer can store the products
for a longer period of time – convenience factor. This prevents the
consumer having to do a lot of shopping daily as foods can be safely
bought and stored for an extended period of time.
 There is increased variety in the diet as foods can be imported in to the
country and foods out of season can be consumed.
 The sensory value of the food is improved by the addition of additives. If
additives are not used, many foods which are processed would lose
flavour, colour and texture.
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 Food is safer for longer periods of time as micro -organism infections are
reduced or impaired. This reduces wastage of food in the home.
 Food additives have allowed the development of a wide variety of new
foods that would previously have been unable to be developed.
 They have opened up an area of packaging of foods and so aid the
consumer in term of choice and storage.
 Many new lower fat products would not be available without the use of
additives – related to health improvement.
 Foods are more consistent with additives so that the consumer can buy
standard products.
 Additives allow the use of cheaper ingredients , although these economies
are not always passed on to the consumer.
 Some additives help to minimise nutrient losses during processing and
storage.
Safeguards regarding the use of additives
Food additives are regulated and controlled on a European Union (EU) wide
basis. The relevant directive clearly states that food additives ar e allowed
only if:
 they present no hazard to health at the level proposed
 a reasonable technological need can be demonstrated
 they do not mislead the consumer.
The directive also states that all food additives must be re -evaluated
whenever necessary in the light of changing conditions of use and new
scientific information.
The EU body responsible for evaluating the safety of food additives is the
Scientific Committee on Food (SCF), which is a group of experts composed
mainly of toxicologists.
The SCF has issued guidelines setting out the tests that must be carried out on
food additives in order to demonstrate their safety. The guidelines require an
extensive range of tests to assess the possible risk to the consumer:
 metabolic studies (to understand how the body absorbs, distributes,
metabolises and eliminates the substance)
 genetic toxicity (potential for gene and chromosome damage)
 reproduction and teratogencity studies (life studies, including the potential
for fertility and birth defects)
 chronic and carcinogenicity studies (the potential for causing cancer).
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The guidelines ensure a threshold level exists above which consumption is
unsafe and below which consumption is safe.
The aim of testing is the identification of an adverse effect caused by th e
additive. When the SCF is satisfied with the data collected from the tests, it
reports its findings to the European Union
New additives are rigorously tested and the government advised by the
Committee on Toxicity of Chemicals in Food, Consumer Products and the
Environment and the Food Advisory Committee before permitting new
additives. The committee set an acceptable daily intake (ADI) for each
additive, this being the amount which, in the opinion of the committee, can be
eaten safely each day, even over a lifetime, without risk to health.
E-numbers
The SCF affixes an E-number to any additives which have passed safety tests
and have been approved for use in the UK and in the rest of the EU.
Food law and the control of additives in the UK
 The statute currently in force is the Food Safety Act 1990.
Food additives and their benefits
Preservatives
The function of preservatives is straightforward: to control the growth of
micro-organisms that cause decay in foods and beverages, ensuring this food
and drink is safe for consumers. This results in an increase in transport and
storage times, which is beneficial to food manufacturers.
Applications
Food preservatives are used widely, including in:
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soft drinks and other beverages
cheeses, margarine, mayonnaise and dressings
bakery products
fresh and dried fruit preparations
prepared salads, delicatessen products and pickled vegetables
pasta products, fish and seaweed
Preservatives are not a substitute for good food hygiene practice. No
preservative can bring spoiled products back to an acceptable level or cover
for the effects of poor-quality processing. They must be incorporated into
stringently clean and hygienic methods of production.
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The greatest threat to the quality and safety of food comes from microbia l
spoilage. Microbial spoilage may result in the loss of sensory qualities ,
leading to such things as bad taste, unpleasant smell and poor appearance. It
may result in the loss of nutrients. More importantly it may increase to a
dangerous level the presence of harmful micro-organisms or the toxins
(poisons) they produce. Preservatives help to prevent life-threatening illness
such as botulism poisoning.
Most preservatives today are actually fungistatic in their action, that is they
are used to prevent the growth of fungi moulds and yeasts. Their antibacterial
activity is less pronounced but a combination of preservatives, each with
some antibacterial action, can be used to give all -round protection. Some of
the main preservatives are listed below:
1.
Scorbic acid and its salts (E200–E203) are the most important and
widely used in food preservatives Sorbic acid has two main advantages:
 it is effective over a wide range of foods and beverages
 it imparts no flavour to the products.
Scorbic acid is used in beverages, dairy products, fish and seafood, fat based products, fruit and vegetable products, baked goods and
confectionery products.
2.
Benzoic acid and other benzoates (E210–E219) are used as
preservatives to prevent yeasts and moulds from growing, most
commonly in soft drinks. They occur naturally in honey and fruit.
Benzoates may make the symptoms of eczema and asthma worse in
children who already have these conditions. They may also be linked to
behavioural problems in children.
3.
Sulphur dioxide and sulphites (E220–E228) are multifunctional, acting
as preservatives, antioxidants and stabilisers of colour. They have a
very efficient bacterial effect, more so than other preservatives, and are
therefore used when control of bacterial growth is essential. They are
used in a wide range of products, including soft drinks, packet soup,
dried bananas and apricots, tinned crabmeat, sausagemeat, burgers,
beer, wine quick frozen chips and jams. A few people with asthma have
had an attack after drinking acidic drinks containing sulphites, but this
is thought to be unusual. Food labelling rules, introduced in 2005,
require pre-packed food sold in the UK and the EU to show clearly if it
contains sulphur dioxide or sulphites at levels above 10 mg per
kilogram or per litre.
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4.
Potassium nitrate and sodium nitrate (E249 and E250, respectively) are
not naturally occurring substances. They are multifunctional in the food
industry, having preservative, stabilising and flavouring properties.
There are health concerns about their use. However, without their
contribution there would undoubtedly be many more deaths from the
disease botulism, which is cause by the bacterium Clostridium
botulinum.
Specific benefits to the consumer of preservatives
 They help to keep food safer longer.
 They lengthen the shelf life of foods.
 They enable manufacturers to transport food in bulk, which is cheaper and
keeps costs down for the consumer.
 They protect food from contamination by micro -organisms.
 They prevent wastage of foods for retailers/consumers as shelf life is
extended.
 They can be added to some fruits, eg apples, to prevent browning –
unpleasant discolouration.
Antioxidants
Oxidation can be a very destructive process. Oxidation of food can result in
loss of nutritional value and changes in chemical composition, the unpleasant
and undesirable oxidation of fats and oils , leading to rancidity.
Functions
Antioxidants are added to food in order to slow down the rate of oxidation.
None are capable of preventing the process of oxidation co mpletely. If used
properly they can usefully extend the shelf life of the ingredient and/or the
food product in which they have been used. These additives protect the fat soluble vitamins from combing with oxygen.
The products in which antioxidants are most commonly used are:
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vegetable oil
snacks (extruded)
animal fat
meat, fish, poultry
margarine
dairy products
mayonnaise/dressing
baked products
potato products.
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Antioxidants can be used in pure fats and oils as well as in products which
merely contain them. Even if a food has a very low fat content it may still be
necessary to employ the benefits of an antioxidant.
Some of the main antioxidants used are:
 ascorbic acid – vitamin C (E300), which is used to prevent browning
reactions in fruits and fruit products
 vitamin E (E306), which is added to prevent rancidity in vegetable oils
and polyunsaturated margarines
 butylated hydroxyanisole (BHA-E320) and butylated hydroxytoluene
(BHT-E321), which are also used as antioxidants in a wide range of
products, eg if the food product is to be heated or fried. These two
antioxidants have been shown to have adverse reactions in some
individuals, and are not allowed to be added to foods of young children
and babies.
How do antioxidants work?
In food, substances called peroxides are produced as a result of oxidation of
fat. As fat decomposes and reacts with oxygen, the amount of peroxides rise
and leads to the decomposition of fats and rancidity. Antioxidants stop the
process.
Specific benefits to the consumer of antioxidants
 Antioxidants prolong the shelf life of foods by protecting against
deterioration caused by exposure to air.
 They prevent fats becoming rancid so extending the shelf life, preventing
waste and unpleasant flavours.
 They prevent colour changes in certain products so maintaining their
aesthetic appeal.
Emulsifiers/stabilisers
The purposes of each are as follows:
 Emulsifiers are used to make stable emulsions or creamy suspensions from
oils and fats and water. They are also used in baked foods to sl ow down
the rate of staling.
 Stabilisers are used to improve the stability of emulsions and prevent the
separation of their components. They help maintain the physical
characteristics of a product.
Emulsifiers are amongst the most frequently used types of food additives. The
foods in which they are most commonly found are:
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biscuits
extruded snacks, breakfast cereals
cakes
margarine, spreads
coffee whiteners, topping powders
desserts, mousses
peanut butter
soft drinks
chocolate coatings
caramel, toffees
chewing gum
frozen desserts, ice cream
dried potato.
Emulsifiers are used in a wide range of products for the following reasons:
 To make foods appealing – they have a pronounced effect on the structure
and texture of many products.
 To aid in the processing and preparation of foods – modern high-speed
food processing techniques often require the use of emulsifiers to allow
the product to be successfully produced.
 To maintain product quality and freshness – this role may well be expected
to be filled by preservatives or antioxidants. However, in many products
emulsifiers play a similar role, for example the control of mould growth in
low-fat spreads by creating an emulsion with finely dispersed small
droplets of water.
 To increase choice – the functional properties of emulsifiers often allow a
much wider choice of raw materials for the manufacture , resulting in
greater choice for the consumer in the different product variations. Many
common products would not exist at all, for example low -fat spreads,
fatless sponges. Costs too can be lowered, without reducing the nutritional
value of the food.
Stabilisers improve the stability of a mixture by increasing the viscosity.
Stabilisers are most commonly used in the following foods:
 Ice cream and ice lollies – to prevent the appearance of large, grainy ice
crystals or ice lumps and give ice cream the firm texture, smooth taste and
good keeping qualities associated with the modern product. Ice creams and
ice lollies made without stabilisers tend to have a grainy feel in the mouth.
This is due to the formation of undesirable, large ice crystals. The use of
stabilisers helps to assist the formation of a smooth texture throughout the
ice cream, which enhances its taste, resists melting and, just as
importantly, retains these qualities until the product is consumed.
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 Many reduced fat or low fat products – Many consumers are aware of the
health benefits of reducing their intake of fats and oils. Reduced fat or low
fat versions of traditional products are now being produced . When a
quantity of fat or oil is removed from a product, it must be replaced if the
product it to be comparable with the traditional one. Often the mass is
replaced by adding water and either a gel or thickener stabiliser to restore
the texture.
 Sauces and dressings – to avoid the separation of the oil and aqueous
components. Stabilisers help to maintain many sauces in good condition.
Without their use the sauces, both in sweet and savoury products, would at
least separate into their original components. This is not unsafe but it is
unattractive to the consumer.
Specific benefits to the consumer of emulsifiers and stabilisers
 They prevent the ingredients separating again so maintaining a good
product.
 They allow the manufacturer to produce a consistent p roduct that can
remain stable on the shop shelf and during transport and distribution.
 They improve the consistency of the food.
 They produce special characteristics required in certain products , ie
viscosity (thickness or thinness), smoothness and stability.
 They help produce ‘healthy’ products, eg low -fat spreads, and so
contribute to consumer health.
Sweeteners
The function of sweeteners in a product is to provide a sweet taste.
Sweeteners are used in a wide variety of foods and beverages such as:
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beverages (carbonated, non-carbonated, milk-based and alcoholic)
breakfast cereals
confectionery (including chewing gum)
desserts, fillings and toppings (ice cream, sweet whipped cream)
processed fruit and vegetable products (jam, jellies, baked beans, canned
fruit)
medicines
syrups
salad dressings and condiments
baked goods.
In an attempt to limit energy intake, a great demand has arisen for food and
drinks that have fewer calories (or kilojoules) than their traditional
counterparts. One way to accomplish this is to replace sugar with a sweet
tasting, non-calorific sweetener.
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Another reason for using sweeteners is to provide appropriate foods and
drinks for diabetics. Diabetes results from a failure of the pancreas to produce
a hormone called insulin which regulates the amount of glucose in the blood.
Sweeteners allow diabetics to have sugar -free, sweet-tasting foods.
Sweeteners fall into two categories:
 Intense sweeteners are many times sweeter than sucrose and they are
therefore used in low concentrations.
 Bulk sweeteners are about as sweet as sucrose and hence are used in
roughly equal amounts.
There are five permitted intense sweeteners:
1.
2.
3.
4.
5.
acesulfame potassium is used in canned foods, soft drinks and table top sweeteners
aspartame is used in soft drinks, yoghurts, dessert and drink mixes and
sweetening tablets
saccharin (and its sodium and calcium salts) is used in soft drinks,
cider, sweetening tablets
thaumatin is used in sweetening tablets and yoghurt
neohesperidine dihydrochalcone (NHDC, E959) is used in soft drinks
and pharmaceutical preparations such as vitamin pills.
The bulk sweeteners are as follows:
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mannitol (E421) is used in sugar-free confectionary
sorbitol (E420) is used in sugar-free confectionary and jams for diabetics
xylitol is used in sugar-free chewing gum
lactitol (derived from whey, a by-product of cheese manufacture) is used
in reduced-sugar jellies and jams.
Specific benefits to the consumer of sweeteners
 Sweeteners can reduce the sugar content of the diet , help weight reduction
and help meet the dietary target for reducing sugar consumption.
 Sweeteners have little or no energy value and can therefore aid weight
reduction as they have a lower energy value.
 Sugar substitutes especially intense sweeteners can be used in the ‘lite’
market for foods and can therefore help reduce the energy value of these
products, assisting in weight reduction.
 Sweeteners can be used in confectionery, bakery goods and many other
foods, increasing the range of ‘healthy’ options available and giving the
consumer a wider choice of products.
 Bulk sweeteners are used in sugar-free confectionery and can help reduce
the risk of tooth decay and obesity.
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 Sorbitol does not require insulin to be metabolised and is therefore used in
products suitable for diabetics, eg jam/jellies, increasing their food choice.
Flour improvers
These substances are used to strengthen doughs.
Specific commercial additives
1.
Anti-foaming agents
These are capable of preventing or stabilising any foams produced
during manufacture, eg glucose mixture, which is transported around
food factories in pipes, could change texture if an anti -foaming agent
was not added. They are also used in cooking oils and bottled beers to
prevent over-foaming.
2.
Colours
The purpose of adding colour to food is to improve its general
appearance. Colour additives are used for sensory purposes such as
taste, smell and appearance. They can be added to replace natural
colour lost during food processing. The examples of foods which
contain added colours is extremely varied from soft drinks,
confectionery and sauces through to tinned peas, soups and fish fingers.
When colours are used in food, they must be declared in the list of
ingredients as ‘colour’, plus either their name or E -number.
Colouring of food products takes place for the following reasons:
 To enhance the natural colour. The ingredients used to produce a particular
food may well have their own colour. However, this is often weaker than
the colour normally associated with this food an d its flavour.
 To ensure uniformity of colour in foods from batch to batch. A food such
as jam bought in December would be expected to look like a similar pot
bought in August.
 To replace colour that may have been lost during the processing
procedures and subsequent storage of the product. Colour can also be
bleached out by the use of preservatives or affected by light during lengthy
storage.
 To add colour to those products which otherwise be entirely lacking in
colour. Many drinks and boiled sweets fall in to this category.
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Consumers’ expectation of food quality is to a certain extent colour dependent. Many permitted colours are of natural origin and they include
saffron, cochineal and carotenes. The list of permitted colours includes some
synthetic dyes. Thousands of such substances are known but most are too
toxic to be used in foods and some are known to be carcinogenic (ie able to
cause cancer). For this reason only a limited number have been approved for
use in food. Most of them are approved for use t hroughout the EU (ie they
have E-numbers). Colouring matter must not be added to meat, fish, poultry,
fruit, cream, milk, honey, vegetables, wine, coffee, tea and condensed or
dried milk. No colours may be added to foods intended for babies and infants
except riboflavin (and its phosphate), lactoflavin and beta-carotene, all of
which occur naturally in other foods. It is the use of synthetic dyes that has
probably attracted most criticism from the anti -additive body.
Research has shown that some colourings may cause allergic reactions,
irritation to suffers of asthma and eczema and may cause
behavioural/hyperactivity problems in children. The Food Standards Agency
has issued advice to parents that if their child shows signs of hyperactivity
then they should avoid giving them food which contains the following
artificial colours: sunset yellow, quinoline yellow, carmoisine, allura red,
tartrazine and ponceau 4R. These colours are contained in soft drinks, sweets,
cakes and ice cream. The FSA are encouraging ma nufacturers to work
towards finding alternatives to these colours.
The final choice is dependent on a number of factors:
 For products with a long shelf life, such as soft drinks , which are bottled
in transparent containers, light stability is an importa nt factor.
 Some colours are sensitive to the discolouration brought about by reducing
agents such as vitamin C. In some cases colours not sensitive to this
particular reaction must be used.
Specific benefits to the consumer of colourings
 Colouring restores the colour lost due to processing so improving
appearance.
 It enhances the colour of certain foods to make them more attractive.
3.
Flour bleaching agents
These substances are added to flour in order to whiten it, eg chlorine
dioxide.
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4.
Flavour and flavouring enhancers
Function
Flavourings are added to food products to give, enhance or intensify flavour.
There are several thousand flavouring agents available to the food industry ,
including both natural and synthetic flavours. At present flavourings may be
used in foods without restriction. It is intended that they will, in time, be
subject to control in the same way as other additives. The problems to be
overcome in doing so, however, are very great because of the large number of
flavourings available and the minute concentrations in which they are used.
Natural flavouring agents include essential oil of cloves and oil of lemon.
Herbs and spices contain many essential oils and other flavouring compounds
and are widely used as flavouring agents.
Synthetic flavours are usually copies of natural forms.
Flavourings are used in a wide variety of food products, for example:
 some products, such as ice cream and margarine, would be unacceptable
without the addition of flavourings
 new foods, such as meat substitutes made from spun vegetable protein,
would, without added flavour, be uninteresting, despite being extremely
nutritious
 some products, such as table jelly, would be completely lacking in flavour
without the addition of flavourings
 some products, such as strawberry yoghurt, have natural flavour present
but possibly at a low intensity. Flavourings may be added to enhance the
natural flavour.
Flavour enhancers
Monosodium glutamate (E621) or MSG as it is commonly known, is the most
widely used flavour enhancer. MSG is a sodium salt of glutamic acid, an
amino acid that is a common component of proteins. It occurs in soy sauce,
which is made by fermenting soya beans, and it has long been used in this
form as a flavour enhancer in Chinese food.
Most dehydrated soups and stock cubes contain MSG and it is also present in
many other ‘meaty’ prepared foods. Some people react unfavourably to MSG
and suffer from what has come to be known as the ‘Chinese restaurant
syndrome’ if they eat food containing it. This c an result in palpitations, chest
or neck pain and dizziness. The cause is not known and the ill -effects soon
disappear. MSG is not thought to be harmful but, as a precautionary measure,
it is not now added to food manufactured for babies and infants.
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The flavour-enhancing capacity of MSG is much intensified if it is used in
conjunction with inosine monophosphate (E631) or guanosine monophosphate
(E627), which are known as IMP and GMP, respectively.
Specific benefits to the consumer of flavour or flavouring enhancers
 Makes flavour in some foods stronger.
 Added to foods in small amounts to improve taste.
 Added to foods in small amounts to give odour.
 Used to produce artificial flavours in foods where ‘real’ flavours may add
to cost (eg yoghurt).
 Used to add flavours to foods which, when processed, cannot replicate
natural flavour.
5.
Nutritional additives
Nutritional additives are added to food to maintain nutritional value and
also to improve the product. This is known as ‘food fortification’. In
some cases the added nutrients replace those lost during processing.
Such addition of nutrients may be either a legal requirement to
safeguard public health or may be completely voluntary by the
manufacturer.
Some examples of legal requirement are:
 the enrichment of margarine with vitamins A and D to make its
vitamin content equivalent to that of summer butter is obligatory
 the addition of nutrients, eg calcium, to flour.
Some examples of a voluntary additions by the manufacturer are:
 fortification of breakfast cereals with a range of vitamins and
minerals
 the addition of vitamin C to soft drinks and juices.
By adding nutrients to basic, low-cost foods, people on low incomes are
able to purchase these foods and so ensure these nutrients in the diet.
Refer to Biochemistry, preservation and processing: Functional foods
6.
Humectants
These substances absorb water and therefore help to prevent food from
drying out. Glycerol is added to sweets and icing for this purpose.
Sorbitol is added to packaged cakes, bread a nd pastries.
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7.
Anti-caking agents
Anti-caking agents or free-flow agents are added to foods and food
ingredients, usually when they are in powdered form. Many food
processing plants have problems with handling powders due to:
 the nature of the powders
 the design of the machinery
 a combination of these factors.
Improving the flow characteristics of the powders can improve the
efficiency of the manufacturing process. Examples of foods that contain
anti-caking agents are:
 Vending machine powders – These are exposed to high humidities
and temperature. Their flow must be maintained to ensure
dependable machine operation and consistent measures. Chocolate,
coffee, soup powder, meat extracts and dried fruit drinks are all
materials which can have flow problems.
 Milk and cream powder substitutes (non-dairy creamers) – These
normally have a high vegetable oil content, causing the particles to
stick together during processing, packaging and subsequent storage
and use.
 Cheese – Cheese which has been grated for convenience of use, eg
pizza topping, tends to stick together because it is compressed during
storage. This undermines the benefit of the grating to the user.
 Sugar – When subjected to a humid atmosphere, sugar, especially
icing and brown, tends to cake easily. Incorporation of a free-flow
aid before grinding will prevent adhesion of the sugar to processing
equipment. It also reduces the tendency of the powdered sugar to
cake.
8.
Acidulants
Acidulants are food additives used to impart a sharp, characteri stic taste
to foods. They also assist in the setting of gels, eg jams , and act as
preservatives. As the food industry has developed, so has the growth in
production of processed foods. Many of these need the inclusion of an
acidulant to impart an acidic or sour taste.
Many foods are quite strongly acidic and the clear sharp taste is due to
the natural acids found in the food itself, eg lemons are rich in citric
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acid and yoghurts contain lactic acid. Acidulants find wide use in
processed foods such as soft drinks, desserts, jams, sweets, soups and
sauces. They contribute to taste but are also used to preserve foods by
creating an acid environment that prevents the growth of microorganisms. Citric acid, originally extracted from lemons but now
manufactured by a fermentation process, is the most likely acidulant.
Phosphoric acid is used in cola drinks to compliment and accentuate the
characteristic cola flavour.
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Resource management
Content
Elaboration
Biochemistry, preservation and
processing
Organic food
Organic food
Organic agriculture is a safe, sustainable farming system, producing healthy
crops and livestock without damage to the environment. It avoids the use of
artificial chemical fertilisers and pesticides on the land and the use of
genetically modified organisms (GMOs) is prohibited. It relies instead on
developing a healthy, fertile soil and growing a mixture of crops. In this way,
the farm remains biologically balanced, with a wide variety of beneficial
insects and other wildlife to act as natural predators for crop pests and a soil
full of micro-organisms and earthworms to maintain its vitality. Animals are
reared without the routine use of an array of drugs antibiotics and wormers
that forms the basis of most conventional livestock farming .
The Organic Food Federation has explained organic food as follows:
‘In order to receive a Certificate of Registration, a grower of organic food has
to prove that he does not use any agro -chemical inputs and has not done so
during a conversion period of two years. All the organic raw materials are
supplied from certified organic sources. In order to use the word organic as
part of a product or description of a manufactured product, it must have no
less than 95% of its agricultural raw materials produced or grown organically.
Only ingredients and additives which are specifically nominated for use by
the regulations may be used in any organic formulation. Certification is
provided by independent inspectors approved by the UK Register of Organic
Food Standards (UKROFS).’
Organic standards
‘Organic’ is a term defined by law and all organic food production and
processing is governed by strict set of guidelines.
Producers, manufacturers and processors each pay an annual fee to be
registered and are required to keep detailed records ensuring a full audit track
from farm, or production plant, to table. Any major infringement of this
results in suspension of licence and withdrawal of products from the market.
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All organic farmers, food manufacturers and processo rs are annually
inspected, as well as being subject to random inspections.
The standards are stringent and cover every aspect of registration and
certification, organic food production, permitted and non -permitted
ingredients, the environment and conservation, processing, packaging and
distribution. The standards are regularly updated and are then enforced by
certification bodies – most of which operate higher standards than are
required by law.
The governing body in the UK is the independent UK Register of Organic
Food Standards (UKROFS), which sets the basic standards to which the
various organic bodies and producers have to adhere to. UKROFS standards
in turn conform to the European Union directive for organic production.
Each certification body has its own symbol and EU code number. These are
the marks to look for on organic products, and are visible proof that they have
met the required UKROFS standards and any others above those set by that
certification body.
The two most important certification bodies are those detailed below.
1.
UK Register of Organic Food Standards
UKROFS is an independent body set up to regulate the production and
marketing of organic food.
The UKROFS standards set strict requirements on the use of manures,
fertilisers and mineral additives. They require crop rotations and list
permitted methods and substances for pest and disease control. They also
require methods to consider the environment and wildlife habitats and specify
certain packing materials. Farms and production pr ocesses must be regularly
inspected and farmers must keep detailed records.
Producers registered with the following certification bodies may also use the
UKROFS logo if they wish to.
2.
Soil Association Certification (SA Cert)
This is the country’s leading certification body, certifying approximately 70%
of organic food produced in the UK. It was founded in 1946 and its symbol is
probably the most familiar to consumers. It operates its own set of standards,
which are more specific and generally stricter than those laid down by
UKROFS. The Soil Association investigates farming methods and advises
consumers on organic methods. They promote organic methods and produce
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to consumers and publish information which help consumers make wise
choices in supermarkets. The consumer is reassured that the food displaying
the symbol is of an organic nature.
To avoid confusion with non-organic produce, most organic food is pre packaged. Always check for the symbol and/or number of recognised
certification bodies. Where produce is sold loose, proof of certification must
be available to consumers.
All manufacturers must be registered with a certification body. Some shops
pay a certification fee to register as organic in their own right. This gives
added assurance to customers. Any shop that repackages goods out of sight of
customers, or cooks its own food and labels it ‘organic’, must also have its
own licence to do so.
Consumers are also protected by:
1.
2.
the Advertising Standards Authority
trading standards.
The Advertising Standards Authority
In relation to organic food the Advertising Standards Authority will:
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prevent false, misleading advertisements promoting organic food
investigate complaints against advertisements or advertisement claims
ensure a standard of advertising that consumers can trust
protect consumers from advertisements which aim to mislead them into
buying the food
 investigate advertisement claims to ensure they are truthful.
Trading standards
In relation to organic foods, trading standards are responsible for enforcing:
 the Trades Description Act of 1968 – this protects consumers from traders
who either deliberately or accidentally mislead their customers
 Food Labelling Regulations under the Food Safety Act 1990.
There are several advantages of buying organic foods:
Nutritional
 Much research has been undertaken into the nutritional content of organic
food. A recent independent review commissioned by the Food Standards
Agency has shown there are no important differences in the nutritional
content or any other additional health benefits of organic produce as
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compared to conventionally produced foods. Only a small number of
differences in nutrient content were found to exist between organically and
conventionally produced crops and livestock.
 It is claimed that organic milk is naturally higher in omega -3 fatty acids,
vitamin E and vitamin A (beta-carotene) than non-organic milk.
Health
 Only 32 of the 290 food additives approved for use across the EU are
permitted in organic food so this will appeal t o consumers who have
concerns about additives in food.
 The Soil Association have banned the use of the following:
– phosphoric acid, which is a highly acidic ingredient used in cola drinks.
It can leave the bones brittle and porous and lead to osteoporosi s.
– aspartame, the most widely used artificial sweetener. Reported reactions
to aspartame include headaches, nausea, diarrhoea, convulsions and
seizures.
– monosodium glutamate, which is thought to be responsible for
dizziness, headaches and asthma attacks.
– sulphur dioxide, which can often cause problems in people who have
asthma.
– hydrogenated fat, which is linked to heart disease.
 Consumers buy organic food because they believe it is free from chemicals
or pesticide residues and therefore better for health, with fewer side effects
or allergies. It is seen as a safe, nutritious, unadulterated food. Over 440
pesticides are routinely used in non-organic farming and residues can be
found in the food.
 Scientists are divided over the issue of whether pe sticide residues in food
and drink do us any harm or not. Many think that residues don’t pose any
significant health risks, but some scientists remain uncertain about the
long-term health risks.
 Organic food is free of hormones and antibiotic additives, wh ich may be
injected into some farm animals or added to the food to speed up growth.
These can find their way into the food chain and are linked with bacterial
resistance in humans to the same or closely related antibiotics.
 Consumers are reassured that organic food does not contain GM
ingredients.
Environmental
 People buy organic food because it doesn’t damage the environment. Many
farmers changed to organic methods because they too felt that invasive
farming techniques were destroying the land and enviro nment.
 Concerns over pollution – non-organic agriculture uses artificial
fertilisers/pesticides, which can add to water pollution and affect river
fish.
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 The ‘green’ image may appeal to some consumers. It is considered that
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organic farming produces crops and livestock without damaging the
environment.
Concern for animal welfare is another factor that may encourage
consumers to buy organic. Animals are reared without routine use of
drugs, antibiotics and wormers.
One of the main goals of organic farming is to develop ‘sustainable
agriculture’. This means resources are retained and recycled within the
farming system. For example, most organic farms have cattle and their
manure is used to fertilise the soil. This helps farms to remain biologically
balanced.
Pesticides are designed to kill living organisms , so while they kill
unwanted pests they might also kill beneficial insects such as ladybirds
and bees as well as harming wildlife. A wide variety of beneficial insects
and wildlife can act as natural predators for crop pests.
People concerned with ‘food miles’ may choose to buy from local farmers’
markets, which sell organic foods.
Consumer choice
 Many people buy organic foods as they believe they taste better than non organic. This could be because organic f ruit and vegetables tend to grow
more slowly and have a lower water content, which may contribute to the
flavour. As yet there is no consistent evidence that organic food does taste
better.
 Vastly increased ranges in supermarkets means there is a much wide r
range of goods to choose from and there is increased promotion of organic
products.
 Increased demand is bringing cost of organic foods down.
 Increased popularity of delivered organic vegetable ‘box’ schemes.
 It has become more fashionable to choose orga nic food; it is now seen as a
mainstream choice as opposed to something unusual to purchase.
 Some councils use local organic produce to support local communities , so
encouraging consumption.
 Organic food comes from trusted sources. All organic farms and fo od
companies are inspected at least once a year to ensure the standards for
organic food are being met. This is reassuring for consumers.
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There could be several disadvantages to buying organic foods:
Cost
 Higher price for organic food makes it too expen sive for those on a lower
income. The cost of organic produce is much more expensive compared to
non-organic produce. Foods can be more expensive due to:
– packaging costs – because organic fruit and vegetables have to be kept
separate so that they do not get mixed up with conventional fruit and
vegetables, most are packaged, which adds to the cost.
– farming methods
(a) The price of organic food is also pushed up by the traditional
farming methods on which it relies. Organic farming prohibits the
use of synthetic fertilisers, pesticides and growth regulators, and
uses biological pest control and mechanical weeding
(conventional growers spray on herbicides to kill weeds).
(b) Organic farms tend to be smaller so their scale of production is
smaller. They, also rely on crop diversity (planting several
different crops) rather than concentrating on a single crop to build
soil fertility. But this means it is not always economic to use large
specialised, often expensive machinery for harvesting and packing
produce. Using more manual labour and less efficient machinery
increases costs.
– Storage and transport
After harvesting, produce is usually stored. Conventional farmers often
use post-harvest treatments to prevent pests, moulds and other damage
to their food while it is in store. Organic farmers do not use these
treatments: instead they put their produce in cold storage. This costs
more and is less reliable so organic farmers can lose more of their
produce than other growers at this stage. Even transporting and sorting
organic food can be more expensive, mostly because of the small
volumes involved. It is likely that prices could fall as farmers invest in
equipment that will result in an increase in production.
 Smaller-scale farming means lower yields and this affe cts availability and
cost.
Nutritional
 Some scientists believe there are no nutritional benefits so consumers
would be spending more money with no added nutritional benefit.
 One study has shown that organic chicken is less nutritious, contains more
fat and tastes worse than free-range or battery farmed meat, in addition to
being more costly. Organic chicken contains lower levels of the
antioxidant vitamin E, which preserves the flavour of the meat. It also ha s
lower levels of omega-3 fatty acids and some chicken has higher
cholesterol levels.
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Health
 Allegations have been made about the safety of organic food production
and the occurrence of E. coli bacteria in the manure used as fertiliser.
There is still much debate over this issue. Organic farming is less likely to
be a source of E. coli contamination and should therefore produce safer
food because organic livestock is far less likely to harbour these dangerous
bacteria, which are not favoured by the healthier lifestyles inherent in
organic farming.
 High levels of toxins in organic foods could be hazardous to health , eg
green potatoes.
 Foods may be contaminated by copper - and sulphur-containing fungicides.
Environmental
 There is now concern that the increasing industrialisation of organic
farming to meet demands has led to a dilution of its ‘green’ credentials and
quality.
 A recent government report claims that despite its eco -friendly image,
some organic farming creates greater pollution and contributes to global
warming.
 Certain organic foodstuffs, such as milk, chicken and tomatoes, produce
more greenhouse gases, create more soil and water pollutants and require
more energy and land for their production than those farmed by
conventional methods.
 May have an adverse effect on the sustainability of farming particular
crops. Natural pesticides produced by plants can be more harmful than
synthetic ones.
 Some consumers may have concern over foreign organic food standards
and authenticity.
 According to the government’s Pesticide Residues Committee, over 40%
of all non-organic fruit, vegetables and bread tested in 2005 contained
pesticides. Organic farmers do not use synthetic chemicals. However, there
is no guarantee that organic food is always completely residue -free.
Pesticides can linger in the soil over many years.
 Pesticides can drift over from conventional farms so crops would not be
able to be termed truly ‘organic’.
Consumer choice
 Appearance of foods, especially vegetables, may not be as standard and
appealing as non-organic so may not appeal to consumers.
 Fresh vegetable products may not have such a long shelf life.
 Some consumers may have concern over foreign organic food standards
and authenticity.
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Imported organic food
Each EU country has its own national organic certification authority which
conforms to EU standards, much like UKROFS, and within each there are
various certification bodies. As in the UK, each certification body may apply
additional specifications on top of the EU standards. EU standards, in turn,
are subject to those laid down by the International Federation of Organic
Agriculture Movements (IFOAM).
For food imported from outside Europe into the EU, the situation is slightly
more complicated, but it is still subject to the same rigorous checks and
guarantees. Imported produce must come from countries recognised as
applying equivalent standards and inspection procedures or , where national
standards do not exist, importers may apply on behalf of specific organic
producers. They are then inspected by one of the EU recognised certi fication
bodies and thereafter subjected to annual inspections in the usual way.
Storage facilities for imported produce must be open to inspection at all
times.
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Resource management
Content
Elaboration
Biochemistry, preservation and
processing
Genetic modification
Genetic modification
Biotechnology has been used in the production of foods, eg cheese, yoghurts,
wine and bread, for a long time. However, the potential of biotechnology has
been expanded enormously in its ability to genetically modify o rganisms.
What is genetic modification?
Every organism has its own ‘blueprint’ in its genes. Genetic modification
means making changes to those genes and in the way they are combined.
Genes hold all the information about the characteristics of any livin g thing
and are made up of DNA. Genetic modification is carried out by either
altering DNA or by inserting genetic material from one living thing to
another. Genes can be introduced from one plant to another plant, from a
plant to an animal, from an animal to a plant or from an animal to another
animal.
Genetic engineering could change agricultural and food processing industries.
It could replace traditional techniques of producing new animal and plant
varieties. Whereas traditional breeding techniques ge nerally limited crossbreeding to animals or plants that were related, genetic engineering allows
genes from almost any form of life to be introduced into any other form of
life. Organisms produced using these techniques are called genetically
modified organisms (GMOs).
Genetic engineering includes a number of different techniques and is part of
biotechnology. The most important technique is termed ‘recombinant DNA
technology’. This involves using an enzyme to cut the DNA, inserting a
second piece of DNA, often containing another gene from a different species,
and sticking them together. It is often referred to as ‘gene splicing’ because it
is similar in principal to splicing pieces of tape together. By this method, the
gene can be identified that will give the desired effect, eg leanness in a farm
animal or a pest resistance in a crop. The desired gene can then be inserted
into the plant or animal.
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Other biotechnology techniques are:
 cloning, where cells, organisms or genes are copied identically
 cell fusion, where cells are joined
 fermentation, in which micro-organisms are grown.
All kind of organisms are modified from bacteria. The aims of these changes
are various, eg:
 to reduce crop losses and food production costs
 to alter the quality, flavour, etc of the food.
The importance of genetic modification
Genetic modification is widely predicted to be of great importance for
economic development. However, much controversy exists over GM foods.
Arguments for the genetic modification of foods
Crop development
 Fewer crops are lost as biotechnology has helped to reduce losses to our
food supplies by using genetic modification to make food crops resistant to
disease and pests, eg a variety of maize (corn), first grown in North
America, is resistant to the corn borer insect, which can destroy up to 20%
of a crop. This achieved by altering the genetic make up of the plant so
that it produces a new protein that enables it to resist the insect.
 Genes can be ‘switched’ on or off to change the way a plant or anim al
develops. Herbicides are used to kill weeds in fields of crops but they can
also affect the crops that they are trying to protect. By using genetic
modification, a gene that is resistant to a specific herbicide can be
introduced into the crop plant so that when the field is sprayed with
herbicide it will kill the weeds but not affect the growth of the crops. An
example of this is:
– general purpose herbicides, which kill a wide range of growing soya
plants, can only be used before the crop emerges from t he soil. Once the
crop is visible a more selective herbicide or weed killer ha s to be used
to combat weeds without damaging the crop. A variety of soya has now
been modified to produce a protein which enables it to tolerate the
general purpose herbicide. Farmers can therefore control weeds
amongst the growing soya plants and choose the best time at which to
spray for maximum effect. It is claimed that, since less of this herbicide
is needed to control the weeds compared with selective weed killers ,
this technology offers a number of benefits. Using fewer chemicals is
considered better for the environment and also saves energy because of
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the lower use of farm machinery. Additionally, better crop management
leads to higher yields and improved crop quality.
Altering the DNA of a plant can also make it more resistant to insects that
attack it, so increasing crop yield.
It may also be possible to further reduce the need to use pesticides on our
crops without risking poor harvests, which can result from disease.
In some common crop diseases, the crop continues to look healthy for
some time after it is infected. By the time the effects of the disease appear,
it may have done significant damage. This means the farmers often spray
against diseases as a precaution and therefore may be applying pesticides
when there is no disease in their crops. By using diagnostic kits farmers
could tell whether their crops were infected and spray only when the
disease was present. This would ultimately benefit the consumer.
Genetic modification can enable plant breeders to develop new crops much
more rapidly and with more certainty that their new variety will do what
they want. Conventional plant breeding is slow and uncertain. Using two
distantly related varieties in order to combine their best characteristics –
for example yield in one case and drought tolerance in the other – is a
laborious process and it can take many years to achieve some degree of
success. If genes for drought tolerance can be identified, it might be
possible to snip them out of that variety and splice them into a high
yielding one, significantly speeding up the development of a new, useful
variety of crop.
Genetic modification makes it possible to transfer genes between plants
that do not usually breed with one another. This could help breeders make
useful changes to crop plants which are difficult to make at present:
increased levels of nutrients such as vitamins, better taste and texture,
improving keeping quality and higher resistance to pests and diseases are
examples.
Two other examples are drought-resistant crops and nitrogen-fixing crops.
Drought resistance in plants would enable farmers to extend both the
growing season and the number of places where the crops could grow. This
is not just a problem in hotter countries, as water availability is a limiting
factor nearly everywhere plants are grown, even in the UK. Plants need
nitrogen to grow. Certain bacteria, found in the roots of peas and beans ,
can take nitrogen from the air and covert or ‘fix’ it for use in plant growth.
Scientists are trying to use genetic modification so that these bacteria can
live in the roots of cereal crops to provide a ready -made source of
fertiliser. This could be cheaper and more environmentally friendly than
the fertilisers used at present.
Reduces losses in the supply of certain foods such as crops and so results
in a constant supply of food and stable pricing. This also means less waste
for the retailers.
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Animal farming
 Genetic modification in the animal world is much less d eveloped than in
the plant world. It is also far more controversial. Subject to the
controversy being resolved, modern biotechnology could bring about a
number of benefits, not just for humans but also for animals. Some
examples of possible benefits are given below:
– Vaccines – Genetically modified medicines are being developed to
protect cattle, pigs and poultry against a variety of serious diseases.
– Disease diagnosis – When vets take samples from sick animals it can
take several days for them to be analysed. In the future it could be
possible for problems to be analysed on the spot with diagnostic kits
developed with biotechnology. This is obviously better for animal
welfare.
– Reduced stress – Some pigs suffer from porcine stress syndrome, a
genetic disorder which causes distress for the animal and has an effect
on the quality of the meat. A simple DNA test has been developed to
identify those pigs affected so that breeders will be able to eliminate the
condition for the benefit of future generations.
– Cloning – This is a technique that has attracted much attention. At its
simplest, cloning is what happens when cells divide , producing more
cells of the same type. This is how yeast, bacteria and other simple
living beings reproduce. In reproductive cloni ng, cells are taken from
an animal and cultured in the laboratory. The genetic material is then
removed from just one of these cells and placed into an egg which has
had its genetic material removed. This egg is then planted without
fertilisation by sperm, into a surrogate mother, where it develops. Dolly
the sheep, born in 1996, was the first example of reproductive cloning.
Using this technique, farmers could incorporate into their herds the
genetic make up of animals with the most desirable genetic trait s, eg
better yield of milk, higher quality of meat , etc, without having to breed
from the donor animal itself. However, reproductive cloning is not yet a
technique that could have general applications in farming. It is
extremely expensive and although in theory a simple process, the
physical production of cloned animals is extremely difficult.
– Genetic modification can also be used to increase the amount of food
we get from animals, eg faster growing, larger fish such as Tilapia are
being developed, which could be particularly beneficial in areas such as
parts of Africa, where protein are relatively limited.
Preservation
 Genetic modification can assist in the preservation of food by preventing
the ripening of fruits and vegetables, enabling a longer shelf life.
 Longer-lasting fruit and vegetables are possible. Genetic modification is
used to slow down softening and provides fruits that last longer. Tomatoes
with this characteristic are sold in the USA. A similar tomato grown in
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California and processed into tomato puree is on sale in the UK. Slowripening apples, raspberries and melons have also been produced and this
benefit is likely to be transferable to other fruit and vegetable crops ,
including bananas, pineapples, sweet peppers, peaches, nectarines, mangos
and strawberries. The farmer in the third world will benefit from such
crops.
 It can increase the shelf life of fresh food without the use of preservatives
or additives. The is advantageous for individuals with food intolerance.
Consumer choice
 Genetic modification can increase and improve the variety, flavour,
texture, appearance and quality of food and so increase consumer choice,
for example:
– tomatoes which do not soften with age and have been engineered by
turning off the softening gene in the plant
– potatoes have been given resistance to potato leaf roll virus, a major
disease of this crop
– the ‘ice-minus’ bacterium, when applied to plants, competes with
bacteria that promote ice formation on plants, resulting in prevention of
frost damage to potatoes and strawberries
– research is being conducted to genetically modify yeast in order to
make bread rise quicker and for use in the brewing industry.
 An improvement in quality, flavour and texture is possible in a wide
variety of foods. Many consumers would like tastier tomatoes that do not
bruise easily. Genetic modification of existing varieties may be able to
provide these improvements. Some of the best tasting potatoes are very
susceptible to disease whilst less flavoursome varieties are not .
 Genetic modification can produce foods in greater quantities, ensuring
supply. This could also have the effect of lowering the price for
consumers.
 If combined with clear labelling, genetic modification could allow
consumers to make choices concerning the purchase of such products.
 Throughout the ages micro-organisms such as moulds and yeasts have been
used to create many different foods and drinks, eg moulds cause blue veins
in Stilton and Gorgonzola cheese. Genetically modified micro -organisms
could offer many other benefits in food production, eg the genetic
formation for the chymosin enzyme in calf rennet (which cause the milk
clotting reaction) has been identified and copied into yeast cells. These
micro-organisms produce pure chymosin, which is identical to the animal
enzyme. This means that cheese can now be made without using animal
rennet and is therefore acceptable to vegetarians.
Nutritional
 Genetic modification can improve the nutritional value of foods to produce
additional health benefits as follows:
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– Lack of protein is a major cause of malnutrition in many countries of
the world. Genetic modification could be used to produce palatable,
high-protein crops, eg transferring the genetic traits from the pea family
to rice to produce a higher protein rice, hence improving its nutritional
value.
– Modified fat foods, eg maize, soya, oilseed rape (canola) and other oil
crops, could be modified to alter their saturated fat content. A potato
with a higher starch content would absorb less oil during f rying,
providing an alternative method of producing lower fat products such as
chips and crisps.
– Higher vitamin content is possible for fruit and vegetables by modifying
them to contain higher levels of nutrients, eg vitamins C and E. Current
research suggests these changes could offer some protection against
chronic diseases such as certain cancers and heart disease.
– Genetic modification can help to modify foodstuffs to meet consumer
demand, eg leaner meat to help meet dietary targets. GMOs have been
used to produce growth hormones to make animals grow more quickly
and with leaner meat.
The concerns about genetic modification
Consumer choice
 The reaction of consumers to GM foods has been so adverse that
supermarkets have refused to sell GM food to consumers and many
promote products clearly as ‘GM free’.
 Opponents of genetic modification argue that not know enough is known
about the science and that altering the genes could lead to unforeseen
problems in future generations.
 Concern that food should be natural and not tampered with. Nobody really
knows the effect that GM foods will have on the body. Until at least 2009,
no fresh GM produce had been approved for sale or consumption in the
UK. However, many processed foods such as cooking sauces, biscuits and
food coatings will include a low level of GM ingredients if they use soya
or maize as an ingredient.
 Fear of the unknown in terms of ensuring that such developments will not
affect the quality and safety of food.
 Muslims, Sikhs and Hindus have ethical, moral, religious and or cultural
objections to consuming organisms which contain copy genes from
animals that are included in dietary restrictions for their religion.
 Strict vegetarians would object to using copy genes of animal origin in a
plant.
 Genetically modified food needs to be clearly labelled. Currently food
made with GM crops has to be labelled as such. But food made using GM
technology or products from animals which have been given GM feed do
not need to be labelled. This means that consumers ha ve difficulty telling
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if a food has been genetically modified and so could be unaware that they
are eating GM ingredients. For more details see the following section on
legislation affecting genetic modification.
Environmental concerns
 Risks to the environment – consumers may be concerned about the
environmental aspect of genetic modification.
 A main concern of genetic engineering is that copy genes incorporated into
a plant could ‘escape’ and transfer to another species with unwanted
consequences. For example it is argued that herbicide-tolerant crops could
cross-pollinate with seeds and so become herbicide -tolerant themselves.
Thus ‘superweeds’ could be created.
 Some consumers and farmers are also concerned that making crops
herbicide-tolerant might lead to an increase in herbicide use, as the crops
could withstand higher doses.
 GMOs could become the pollution of the future, ie biogenetic pollution.
This is because the organisms are alive and can reproduce, migrate and
mutate. They would be growing, moving and changing the form of
pollution. Once released, they will often be impossible to recall. The Royal
Commission on Environmental Pollution report on the release of GMOs
recognised that some organisms released to the environment will become
established. Most may not be a hazard but some could have serious
environmental impacts.
 Dangers include the threat of GMOs spreading out of control and the
possibility of genetic transfer. This could lead to disruptive changes in the
balance of some species.
 Hybrids of crops and wild plants are common, thus it may be possible for
genes to be introduced into crops to be passed to the wild plant or to other
non-GM crops.
Ethical and animal welfare issues
 Some people, for whatever reason, are often worried by what they see as
being ‘unnatural’ and ‘playing God’, manipulating the basic blueprint of
life for human corporate ends. They question the impulse to totally control
nature for human ends.
 They also worry about the ‘integrity of species’ which is threatened by
genetic engineering. In order to patent a plant or animal it is necessary to
claim that this is an ‘invention’, which is contrary to the view that plants
and animals are part of nature.
 Ethical concerns come into sharp focus when the effect of genetic
engineering on the welfare of animals is concerned.
 Genetic engineering can have detrimental effects on animal welfare. The
effects of inserting a foreign gene into an animal are not always
predictable. More work on genetically engineered animals means more
animal experiments, therefore the gains from such results have to be
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weighed against the suffering that might be caused. During an American
study, cows were rejected with a milk-boosting hormone that caused
metabolic stress and swelling where the cows were injected.
 Some people see such developments as a simply an extension of intensive
farming methods designed to produce food more efficiently. Others believe
that such developments are inherently wrong.
Legislation affecting genetic modification
In the UK, the Food Safety Act 1990 requires that all food must be fit for
consumption, ie it must not be injurious to health, be unfit or contaminated.
A specific set of safeguards controls the use of genetic modification in foods
and food ingredients. These foods are assessed by a number of committees of
independent experts, most of which include consumer representatives:
 The Advisory Committee on Novel Food Processes
 The Committee on Toxicity of Chemicals in Food, Consumer Products and
the Environment
 The Food Advisory Committee.
The Regulation on Novel Foods and Novel Ingredients has been adopted. It
came into force on 15 May 1997 in order to harmonise procedures for the
approval of all novel foods, including those produced using modern
biotechnology.
Special rules govern the labelling of all foods regarded as ‘novel’, including
GM foods. According to EU Regulation on Novel Foods and Novel
Ingredients, adopted in 1997, such foods must be labelled if they are no
longer equivalent to their conventional counter part s. This includes when they
have a different composition, use or nutritional value to the conventional
food, ie fruit and vegetables genetically modified to be higher in vitamins
would be covered by this regulation.
In the EU, if a food contains or consist s of GM ingredients or contains
ingredients produced from GM ingredients, this must be indicated on the
label. For GM products sold ‘loose’, information must be displayed
immediately next to the food to indicate it is GM.
In 2004, new rules for GM labelling came into force in all EU Member States.
The GM Food and Feed Regulations lay down rules to cover all GM food and
animal feed, regardless of the presence of any GM material in the final
product. This means products such as flour, oils and glucose syrups have to
be labelled as GM if they are from a GM source.
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Products produced with GM technology (eg cheese produced with GM
enzymes) do not have to be labelled. Products such as meat, milk and eggs
from animals fed on GM feed also do not need to be labelle d.
Any intentional use of GM ingredients at any level must be labelled.
However, the Food and Feed Regulations provide for a threshold for the
accidental presence of GM material in non-GM food or feed sources. This
threshold is set at 0.9% and applies to GMOs that have EU authorisation.
Genetic modification of food is extremely controversial and will need
considerable public debate to determine if it is acceptable.
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Resource management
Content
Elaboration
Biochemistry, preservation
and processing
Food irradiation
Food irradiation
Definition
 Food irradiation is a process in which food products are exposed to a
controlled amount of radiant energy to kill harmful bacteria.
 The foods are given small doses of radiation while packed in cartons on a
conveyer belt. Radiation is energy transmitted by electromagnetic waves
or rays.
 This is called ionising radiation and is similar to X-rays. Ionising radiation
in the form of gamma rays is very effective in killing micro -organisms that
would otherwise cause food-borne disease.
 When food is irradiated, energy passes through it and harmful bacteria are
killed.
The choice of irradiation method will depend on the substance being treated.
1.
Gamma rays (X-rays, only more powerful)
 Gamma rays penetrate deeply – several feet – and can be used for
preserving food. These rays are emitted by a radioactive isotope and
heavy shielding is needed for safety.
 Since gamma rays are highly penetrating they are able to pass
through large containers of food and thus food, eg an e ntire sack of
spices, can be treated in bulk or in its final packaging.
2.
Beta particles (electron beams or E-beams)
 This is a stream of high-energy electrons propelled out of an electron
gun.
 Electron beams can penetrate food only up to a depth of 3 cm so that
the food to be treated must be no thicker than that to be treated all
the way through.
 Two opposing beams can be used to treat food that is twice as thick.
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EU legislation
Two directives were adopted by the EU in 1999. These permit irradiation
providing it:
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is necessary
presents no hazard
is beneficial for consumers
is not used as a substitute for good manufacturing practice.
Labelling is required. Foods must be labelled as either ‘treated with ionising
radiation’ or ‘irradiated’. At present Member States have their own national
legislations.
UK legislation
In the UK, the Advisory Committee on Novel and Irradiated Foods approved
irradiation I 1986 as a safe and satisfactory method of food processing. In
1991 the Food (Control of Irradiation) Regulations in the UK allowed the
irradiation of food from seven groups in the UK. These groups are fruit,
vegetables, cereals, bulbs and tubers (potatoes, onions, garlic , etc), spices,
fish and shellfish, and poultry. The regulations also make provision f or
labelling to ensure consumers are fully informed whether food or any
contained ingredient have been irradiated. Under the Food Labelling
Regulations 1996, irradiated foods and ingredients have to be identified with
the words ‘irradiated’ or ‘treated with ionising radiation’. In 2001, UK
legislation was amended to implement the changes introduced by the
European directives.
Consumer and other groups who monitor what is in the interests of the public
still remain unconvinced of the total safety and contro l of this technological
development.
Exhaustive studies have been carried out regarding the safety of irradiated
foods. Modern irradiation plants are completely automated and computer
controlled so time and dose levels can be strictly monitored and peopl e are
not exposed to radiation at any time.
Irradiation plants, storage and transport of irradiated foods have to be
licensed and are subject to strict inspection control.
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Arguments for the use of irradiation
Sensory qualities
 Traditional preservation methods, eg drying, smoking, curing, addition of
salt, all change the way the food looks or tastes – irradiation may
overcome this as low levels of irradiation have no effect on the texture or
flavour of food.
Food safety
 Increasing demands and pressures on food production systems in recent
years have led to large sections of the food chain being contaminated, eg
poultry frequently contaminated with salmonella, as much as 75% in
Europe. The contamination problems using conventional methods of
preservation have led scientists to try to improve these techniques;
irradiation may be the answer.
 Irradiation can make foods safe by killing or reducing harmful micro organisms such as salmonella, listeria and campylobacter.
 International organisations such as the UN International Atomic Energy
Agency promote its use, surely meaning it is an economic and viable
method of preservation.
 The World Health Organization has supported food irradiation as it sees it
as a means of reducing food-borne disease.
 Many governments also have concerns about food-borne disease and feel
irradiation is an easy way to provide safe food.
 Many governments have concerns about food shortage and irradiation may
help with this problem.
 Some food-producing countries such as Ghana and Brazil u se
decontamination methods that are presently banned on health and safety
grounds. Irradiation would help the food export problems they are facing
at the moment.
 It also has some specific advantages as a food treatment process in certain
countries, eg it is the only process that can be used to treat raw food such
as the Thai Nahm sausage, which consists of raw pork. It is also the only
way of treating seafoods that are traditionally eaten raw so ensuring food
safety.
 It can completely sterilise a food making it suitable for
vulnerable/immunocompromised patients in hospitals. Foods prepared
under medical supervision for these patients, and products classed as
medicines, are exempt from labelling.
Food preservation
 Some food manufacturers support irradiation as it enables them to extend
the shelf life and storage periods of foods. This allows them to reduce
waste and to deliver foods to the shops when it is economically
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advantageous to do so. Irradiation inactivates enzymes and destroys
spoilage microbes.
 It can delay or stop the ripening/decay process so foods can be stored for
longer.
 It enables foods such as tropical fruits to be transported all over the world
economically.
 It can kill many insects and pests that infest foods such as grains, herbs
and spices without appearing to affect them.
Nutritional
 Protein, fats and carbohydrates undergo little change in nutritional value
during irradiation.
 Similarly, the essential amino acids, essential fatty acids, minerals and
trace elements are also unaffected.
 There can be a decrease in certain vitamins, particularly thiamine, but
these are similar losses to other processes such as drying or canning .
Arguments against the use of irradiation
Sensory qualities
 The irradiation process is not suitable for all p roducts:
– Foods with high-fat contents, such as fatty fish and some dairy
products, develop off-odours and tastes due to the acceleration of
rancidity, even at low doses of radiation.
– Foods with a high protein content, such as meat and poultry, can suff er
changes in flavour and smell after irradiation at ambient temperatures
but these changes can be reduced by irradiating at chill temperatures
and minimised by irradiating at frozen temperatures.
– Milk develops an off-flavour at relatively low doses but various cheeses
show good tolerance of low doses.
– In some fruits, eg peaches, tissues will soften.
 In some foods the dosage is critical: a slight overdose can cause foods to
have an unpleasant taste and texture.
Food safety
 Despite the results from many studies, consumer experts are dissatisfied
with some of the conclusions and argue that key experiments have been
ignored and that risk assessment methods are suspect.
 At the dose given, about 90% of micro -organisms are killed, so care still
has to be taken with foods otherwise the remaining organisms will
multiply. This could mislead consumers into thinking these foods are safer
and as a result they may fail to take necessary measures to prevent cross contamination. The risk of recontamination of food aft er irradiation is very
serious as a near sterile food is an ideal medium for rapid growth of re introduced bacteria.
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 Food irradiation does not inactivate dangerous toxins that have already
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been produced by bacteria prior to irradiation. In some cases, suc h as
Clostridium botulinum, it is the toxin produced by the bacteria, rather than
the bacteria itself, that causes the health hazard.
It is ineffective against viruses and can cause mutations in bacteria and
viruses, leading to potentially resistant strains.
The more initial contamination there is in food, the higher do se of
irradiation it would take to eliminate possible pathogens and the greater
the change in the taste and quality of the food.
Irradiation of food products produces chemical changes, result ing in new
substances called radiolytic products. There is a lot of controversy over
these products and how they might affect the consumers who eat them.
Some of these chemical changes are thought to be harmful – some altering
genetic structure and some causing cancers.
There is concern that manufacturers may exploit the use irradiation to
‘clean up’ foods that have decayed, which will then enter the food chain.
Irradiating fruit and vegetables to extend their shelf life can mislead
consumers by making ‘older’ food look ‘fresh’.
Although there is no hard evidence to show irradiation dosage levels used
are dangerous or have harmful effects, very few of the studies have been
done for any length of time on humans.
Consumer experts fear that changes produced by irradiation may have
subtle chemical effects, but that the results may not show up for many
years.
Studies done have been on selected foods and little is known about the
effects on pesticides and other chemical residues on foods.
Tests done have been in controlled circumstances, and effects may change
when the process is scaled up in a manufacturing environment.
Although all irradiated foods must carry a label intimating the fact, it is
difficult for consumers to detect as the taste, smell, texture and appe arance
of irradiated foods are usually no different to the same non -irradiated
foods. However, a range of analytical methods have been developed and
these are based on the detection of physical, chemical and microbiological
changes that can occur in irradiated food. Nine methods have been adopted
by the European Committee for Standardisation and are available for use
by national standards bodies such as the British Standard s Institute in the
UK.
Nutritional
 Vitamin E levels can be reduced by 25% after radiation and vitamin C by
5–10%. This is compounded by the longer storage times of irradiated
foods.
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Cost
 Food irradiation is not a low-cost method. Irradiation plants are expensive
to operate and this could lead to irradiated foods costing more.
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Resource management
Content
Elaboration
Biochemistry, preservation and
processing
Functional foods
Functional foods
The market for functional foods is growing as consumers become more health
conscious. In 2007, £613 million was spent on them in the UK.
Definition
 A functional food is a food modified in such a way that:
– the amount of a beneficial component is increased or
– new beneficial components are added or
– harmful components are replaced/eliminated or
– a component is added to preserve the beneficial effects.
 Functional foods contain ingredients that have health-promoting properties
over and above their nutritional value.
 They are foods that have been altered to enhance or improve health
through diet and so reduce the incidence of illness o r a particular disease.
Functional foods include a very broad range of products – from foods
generated for a particular functional ingredient to staple foods that have been
fortified with a nutrient.
It is generally accepted that ‘health-promoting’ claims rather than disease
prevention or medical claims can be made. From a legislative point, they are
categorised as foods not medicines. Currently in the UK there is no specific
legislation covering claims for functional foods. The relevant food law that
identifies the boundaries for such claims is embodied in the Food Safety Act
1990, which states that claims must not mislead the consumer as to the nature
or quality of a food, and the Food Labelling Regulations 1996, which allow
declaration of the nutrient content of foods and claims such as ‘low fat’ or
‘high fibre’ but prohibit medicinal claims such as ‘prevents’ or ‘treats’ or
‘cures’ a disease.
It is essential that robust science exists to underpin the claims being made.
Ideally this should include evidence of the following:
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 The substance is absorbed or reaches its site of action.
 Consumption of the food beneficially influences a physiological function
(eg blood pressure) or it is recognised to impact on health (eg blood
cholesterol) and, ideally, that this effect has a direct impact on health
status.
 The level of consumption of the food that is required to achieve a
beneficial effect on health is also an important consideration. In particular,
it should be possible to achieve the required level of intak e of the
functional food or ingredient within normal dietary patterns.
Types of functional foods
1.
Dairy foods
Margarine and spreads
 Currently, spreading fats constitute one of the biggest functional foods
sector in the UK.
 Margarines and spreads, eg Benecol and Flora pro-active, can include the
plant sterols or stanols that have been shown to lower cholesterol and so
help reduce the risk of coronary heart disease (CHD).
 Plant sterols and stanols are found naturally in fruit, vegetables, cereals
and other plant food in small amounts.
 Taking 2–3 g of plant sterols or stanols daily has been shown to lower
cholesterol. In a typical day’s diet approximately 0.4 g of plant sterols or
stanols are consumed.
 The way that these work is by blocking the absorpti on of cholesterol from
the small intestine into the blood, therefore there is less cholesterol
circulating in the blood.
 Research claims that using such products has been shown to reduce low
density lipoprotein (LDL) levels by between 10 and 15% in a few weeks
but are most beneficial to those with high cholesterol.
 Another area is the incorporation of mono - or polyunsaturated fatty acids
so helping to reduce the risk of heart disease through altering cholesterol
levels.
 Some spreads provide omega-3 fatty acids from oily fish, which could help
to lower triglyceride fats in the blood, but the amount of omega-3 provided
is usually insignificant. However, they may be useful to some people who
dislike oily fish and do not eat the recommended amount weekly.
 Margarines, spreads and butter are fortified with vitamin D, which assists
absorption of calcium.
 Bovine milk may be considered a functional food due to the presence of a
number of immunomodulatory factors (conjugated linoleic acid may have
potent anti-cancer and immunomodulatory properties).
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 Milks and yoghurts have omega-3 added and so could play a role in the
prevention of CHD.
Yoghurts/fermented milk products
Another large functional food area is that of yoghurts and fermented milk
products containing ‘friendly’ bacteria, known as probiotocs.
Probiotics
 The history of probiotics, in the form of fermented milk products, goes
back many centuries. It is important that probiotics are strong enough to
survive the acid in our stomach and reach the large intes tine, where they
than can colonise and so balance out gut bacteria. Probiotics are usually
found in types of milk products and yogurts.
 Probiotics are a ‘live microbial supplement’ that improves the intestinal
microbial balance so claiming to promote good intestinal health and act as
an aid to digestion.
 Evidence for the benefits of probiotics has been increasing in recent years,
but this is an area of debate. Evidence includes the following:
– Bifidobacteria may help fight a range of harmful and food poiso ning
bacteria, including the potentially fatal E. coli 0157.
– Lactobacillus GG (a probiotic) can be helpful in treating antibioticassociated diarrhoea. Taking a course of antibiotics may cause major
changes to the balance of bacteria in the gut. Some stu dies have been
undertaken that show probiotics will help protect people from getting
diarrhoea when taking antibiotics.
– Lactobacillus GG has also been shown effective at treating some cases
of traveller’s diarrhoea. Some studies have shown that probiotic s can
reduce the chance of getting traveller’s diarrhoea; other studies have
concluded they will make no difference.
– Other studies have shown that bifidobacteria and Strotococcus
thermophilus, both bacteria found in bioyoghurt, can prevent young
children suffering from diarrhoea in the first place or shorten the
duration of diarrhoeal disease in children.
– Other suggested benefits are inhibition of Helicobacter pylori,
improved well-being among patients with Crohn’s disease, amelioration
of symptoms in adults and children with allergies, and increased
resistance to respiratory infections in children.
– Studies have shown that probiotics may help to reduce the symptoms of
irritable bowel syndrome (severe diarrhoea or constipation, together
with bloating).
 Bio yoghurt that contains lactobacillus acidophilus can reduce the
incidence of vaginal infections, including thrush and bacterial vaginosis.
Gut colonisation of Candida albicans, the thrush causing organism, also
decreases significantly.
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 Supplementing with probiotics may also help reduce certain food allergies
according to some research. This may be because the bacteria reinforce the
barrier properties of the gut so that improperly digested compounds cannot
leak through.
 Some trials have shown a reduction in numbers who tested positive for the
bacteria Clostridium perfringens.
 Probiotics only have a transient effect and regular daily consumption is
needed to bring about health benefits.
Prebiotics
 Prebiotics are non-digestible carbohydrates that selectively stimulate the
growth of beneficial bacteria in the colon.
 Eating prebiotics therefore causes more good gut bacteria to grow in our
gut. Sources of prebiotics in the diet include chicory, artichoke, leeks,
onions, garlic, asparagus and banana.
 Prebiotics are increasingly used in supplements and can have a more long lasting effect as they encourage the growth of good bacteria such as
bifidobacteria already present in the gut.
2.
Fruit/vegetables
 The quality of tomatoes, cereals and other crops may be i mproved in the
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future by using new GM crops with a greater content of antioxidants, such
as natural flavonoids or other phenolic compounds. Because of the healthy
profile of these antioxidants, which are believed to have a protective effect
against cardiovascular diseases and some forms of cancers, these new
crops are considered as functional foods.
Flavonoids are naturally present in most fruits and vegetables. They are as
good antioxidants as carotenoids and vitamins E or C. These antioxidants
are thought to work by scavenging oxygen radicals, thus protecting against
oxidative breakdown of biopolymers such as DNA, proteins and lipids.
Breakdown of DNA molecules in cells is believed to be the most
prominent mechanism for initiation of cancer cells and oxida tion of
lipoproteins for increasing the risk of arteriosclerosis.
Scientists are trying to identify key genes responsible for flavonoid
production and have started to grow the very first generation of tomato
plants possibly high in flavonoids. After comple tion of this work, they will
intend to transfer their knowledge to other crops, in particular cereals.
US scientists have created purple tomatoes, which have the antioxidant
pigment from red wine that is believed to prevent heart disease.
Biologically active plant chemicals known as ‘phytochemicals’ can reduce
cancer risk.
Benefits of garlic added to foods include cancer chemopreventive,
antibiotic, anti-hypertensive and cholesterol-lowering properties.
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 Cranberry juice is recognised as helping in the treatment of urinary tract
infections and may be considered a functional food by some although no
specific ingredient has been added.
3.
Drinks
 Tea, especially green tea, has a beneficial effect on cancer risk and may be
considered by some to be a functional food.
 Drinks are a fast developing area of functional foods, for example some
are fortified with the antioxidant vitamins A, C and E, some with calcium
and others with herbal extracts.
 Some drinks claim to help overcome problems ranging from premenstrual
syndrome to a lack of energy.
 Orange juice with added plant sterols to reduce cholesterol levels is
available in USA.
4.
Meat, fish and eggs
 During the last few years the scientific trend has been to improve the
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5.
health profile of traditional raw materials, eg meat, vegetable oil, dairy
products and grains, using traditional breeding or changed animal feeding.
Improvement of the health profile of beef has been made to produce a
functional red steak. The objective will be met through improvement of the
fat composition by decreasing saturated fatty acids and increasing
conjugated fatty acids (conjugated linoleic acid, CLA) as well as omega-3
fatty acids (Poly Unsaturated Fatty Acid – PUFA) with related health
benefits.
This trend to improve food raw materials by traditional breeding, by
genetic modification or by changing the feeding of animals has resulted in
health improved meat – by improving the fatty acid profile of animal feed;
health improved eggs – by adding fish oils to the chicken feed.
Beef is a source of CLA, which has been shown to modulate tumour
development.
More recently CLA has been investigated for its ability to change body
composition, suggesting a role as a weight-reduction agent.
Eggs with added omega-3 – reduce cholesterol levels, lowering the risk of
CHD.
Cereals and grains
 This is area where calcium and mineral fortification is strong – they are
added to both breakfast cereals and fortified cereal bars.
 Calcium enrichment of foods (and beverages) can allow up to 30 times the
amount of calcium present in an equivalent volume of milk to be
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incorporated. This could address issues such as osteoporosis and other
calcium-related diseases.
Oats are a source of the cholesterol-lowering soluble fibre B-glucan, which
can reduce LDL cholesterol, thereby reducing the risk of CHD.
Soy is thought to play preventative and therapeutic roles in cardiovascular
disease, cancer, osteoporosis and the alleviation of menopausal symptoms.
Flaxseed consumption has been shown to reduce total and LDL chol esterol
as well as platelet aggregation.
Burgen is a bread containing soya flour and linseeds , which provide
phytoestrogens, a natural substance which mimics the structure of the
hormone oestrogen. Phytoestrogens have been said to enhance oestrogen
levels when hormonal level are low (ie at the menopause) or to weaken the
effects of oestrogen when level are high. This action may protect against
both hot flushes and breast cancer. However, quite a lot of this type of
bread would have to be eaten – at least six slices daily on a long-term
basis – for any health benefit to be noticed.
In USA, ‘men’s bread’ is on sale containing soya isoflavones , omega-3
and omega-6.
Breads with the prebiotic inulin added to it are on sale in Germany and
Australia.
In Japan, bread which offers cosmetic benefits is proving popular.
In Germany, bread enriched with L -carnitine claims to boost energy,
particularly among active people/sports enthusiasts.
Development of bread fortified with soya isoflavones and trehalose to
increase calcium absorption is under way.
In UK, Allied Bakers have launched a soy-enriched bread said to lower
cholesterol and improve heart health.
Much research continues into the value of functional foods.
So what are the positive arguments for the use of funct ional foods?
 When taken as part of a balanced diet and healthy lifestyle, functional
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foods have the potential to improve health and reduce the risks of certain
diseases.
Functional foods appeal to some consumers because they are convenient
for today’s lifestyle in bringing about health benefits more quickly than
would normally be the case through eating conventionally healthy foods
alone.
If family history points to heart disease, selecting a functional spreading
fat could help control cholesterol within the family.
Allows consumers to take greater control of their health through food
choices, knowing that some foods will provide specific health benefits.
Some foods, eg breakfast cereals, will provide a reasonably inexpensive
source of additional minerals and vitamins in the diet.
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 Increased ranges are now available so more choice for consumers and
easier to obtain.
 For certain age groups, functional foods may be beneficial. Inactivity, a
poor appetite and a low food intake can contribute to physical frailt y in
elderly people and result in a poor nutritional and health status. One study
undertaken with this age group showed beneficial effects of nutrient enriched foods
Negative points
 Some consumers may come to over-rely on functional foods for added
health benefits instead of learning about dietary advice and consum ing
foods that could provide the same benefits. Functional foods should not be
seen as alternative to a varied/balanced diet.
 Generally, functional foods would have to be eaten in fairly large
quantities and on a long-term basis to effect any improvement on health so
no immediate health improvements occur.
 In many cases, functional foods are more expensive and it is possible to
get the same beneficial ingredients more cheaply and naturally from a
balanced diet.
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Resource management
Content
Elaboration
Biochemistry, preservation and
processing
Fast foods:
 reasons for growth of the fast food
industry
 role of technology
 impact of fast food on food habits
 in a social context, eg schools,
hospitals
Fast/junk foods
The consumption of fast or junk foods has increased hugely in recent years
and with this have come increased levels of obesity, particularly childhood
obesity. Across Scotland as a whole, a third of 12-year-olds were clinically
overweight in 2006, thereby greatly increasing their risk of heart disease,
diabetes and cancer in later life.
One in five children is now considered to be obese. While most childeren are
still not fat, not changing eating habits means nearly all are at risk o f
becoming obese. Eating 200 g of junk food, or a couple of burgers, twice a
week means an extra 59,808 calories a year, which is enough to put on almost
8 kg. A junk food diet can lead to a range of conditions , from heart disease to
asthma or cancer. Type 2 diabetes, usually only associated with adults and
caused by poor diet, has become evident in children for the first time during
the past few years.
The govenrment has attempted to improve chldren’s diet in the fo llowing
ways:
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free fruit in primary schools
healthier school meals and vending machines
restrictions on advertising junk food to children
legislation to promote healthy eating and combat childhood obesity.
The consumption of fast/junk food, however, continues. It is only in recent
years that these occasional treats have turned into daily meals, which is where
the problems start.
While campaigners want to see unhealthy foods banned in schools, others
argue there is no such thing as junk food, only a junk diet.
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What is fast food?
This term usually describes food that is quickly prepared, usually outwith the
home situation. A large percentage of these foods are high in fat, sugar and
salt, and they have often been criticised for their lack of nutrition.
What is junk food?
No-one seems to know where the term ‘junk food’ originated, but it is
generally agreed that it defines any food with little or no nutrients and an
excess of fat and calories. Often this means heavily processed food, but it
doesn’t necessarily exclude meals made at home.
We all think we recognise junk food when we see it: a bag of crisps, a fizzy
drink, chocolate, but what about a prepacked sandwich? A takeaway pizza? A
home-baked cake?
The Food Standards Agency is currently working on defining junk food, using
a model that rates the nutrient, fat, sugar and salt content of the food. The
problem with the current lack of definition is that without agreed terms of
reference it is difficult to introduce guidelines on junk food promotion or to
encourage manufacturers to introduce better labelling.
Why is fast/junk food consumption rising?
Manufacturers
 Junk and fast foods are very tempting. Manufacturers have spent many
years and millions of pounds developing their products to make the m as
attractive as possible.
 Some ingredients are chosen for their practical application – saturated fat,
for example, is used because it is cheap and can withstand cooking at very
high temperatures, but most recipes include plenty of added extras for
sensory appeal.
 Artificial colourings are added to make products more attractive and
appealing for consumers.
 Flavour enhancers such as monosodium glutamate either add smell to food
that has lost it during processing or enhance existing smells.
 Emulsifiers make products such as ice cream smooth.
 Artificial sweeteners such as aspartame or saccharin give a more intense
sweetness than sugar alone.
One reason why habits are proving so hard to change may be the addictive
nature of junk and fast foods. Research has shown that sugar can be addictive
in some circumstances and that eating junk food releases the same chemicals
into the brain which play a large part in drug or alcohol addiction.
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A survey of school children by the Consumers’ Association in 2003 found
that almost half were deficient in zinc; this reduces the ability to taste and
smell and so prompts cravings for very sweet, salty or spicy food.
Reducing the amount of junk food in the diet is not easy. Advertising,
marketing schemes and financial incentives to purchase ‘super size’ portions
all encourage consumption of this kind of food. Recent research showed that
typical menus in fast-food outlets contained 65 calories more per bite than an
average British meal and more than twice that of a recommended healthy diet.
Promotion
Television advertising – although “unhealthy” foods are not allowed to be
advertised during the hours when popular childrens programmes are on
television, children will view about 5,000 television adverts every year with
about 75% of them promoting high-calorie, low-nutrient foods.
The promotion and marketing of junk food is ingrained in everything we do –
from celebrity endorsements to sponsorship of sport and entertainment
events, from enticing displays at the supermarket to glossy features in
magazines.
Lifestyle
 Many parents work and do not wish to spend time preparing meals. A
takeaway or processed foods is seen as an easy option. Fast -food
restaurants are responding to a real societal need – the inability of many
families in which both parents work to find time to c ook for themselves.
 Fast foods are seen as helpful to those who have limited time for
shopping, preparing, cooking and eating foods.
 Many of the fast foods are designed to be eaten quickly and are easily
eaten from the hand.
 Due to the large number of fast-food outlets there is a tremendous
variety of foods on offer. Often these appeal greatly to children because
of the promotional gifts and foods that are provided for them.
 Many fast foods are reasonably priced, quickly and efficiently served ,
and are of consistent quality.
 Double incomes means that there is more money available for buying
processed foods.
 If children are not used to home-cooked meals then they become more
reliant on processed/takeaway foods and so the junk food habit is
continued. Habits then become too hard to break.
 Many teenagers know what they are eating is considered ‘bad’ and
choose these foods deliberately, rebelling against ‘healthy eating’
advice. Fast foods can be low in fruit and vegetable content and high in
fat and salt.
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Encouraging children to eat healthily is not as easy as simply banning
junk food. Junk food should be seen as a special treat, not a way of life.
It may be that attitudes need to change – it may not be what we eat but
the quantities we eat that is the problem.
In Britain, the ‘no-time-to-cook’ culture continues to grow. ‘Grazing’
has become a way of eating – people eating what and when they felt like
it. The belief is that cooking can be abandoned and yet a healthy diet
can still be eaten.
In 2005, the Food Standards Authority admitted that the ever-growing
consumption of ready meals/fast foods was having a bad effect on the
nation’s health and the food industry was encouraged to mak e its
techno-food healthier
Today’s working parents can no longer expect everyone in the family to
eat the same meal as the ‘no-cook’ culture makes it possible for
everyone to something different. As a result shopping now has to take
account of everyone’s likes and dislike. One study found that 43% of
mothers make up three different meals each night.
Role of technology
The increased variety and use of fast-food restaurants has been made possible
by rapid technological change. Such changes include the following:
 The availablity of transport for all families encourages eating out at fast-
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food outlets and the fact that many fast-food restaurants operate a drivethrough facility encourages the consumption of fast foods without even
having to get out of the car to order.
Preservation techniques such as freezing, cooking methods such as
microwaving, kitchen equipment for food preparation and equipment
which monitors and controls temperatures and cooking times have all
contributed to the increase in fast-food consumption.
The demand for standardised products has also resulted in changes to how
food is grown and distributed. The huge purchasing power of fast -food
chains allows them to dictate their requirements with regard to the quality
and quantity of food grown. As a result, fast -food chains can control a
considerable amount of the food supply chain from production,
transportation and preparation to consumption.
Computer technology has also contributed to the operation of fast -food
outlets in the following ways.
Pre-programmed computerised cash registers make it quick to enter
details, price the order and give change.
Computers in some drive-through restaurants allow customers to enter
their order, saving time and staff costs.
Computers can control cooking operations, eliminating human error and
reducing the risk of food poisoning and encou raging consistency of
product standards.
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 With the aid of technology, the supply side has become easier. Standard
amounts are delivered, for example raw ingredients arrive in measured
amounts, hamburgers are of uniform weight. This precise portion control
allows for standardisation of product, cost control and profitability.
Food habits
 Fast foods have become a major feature in many people’s diets as opposed
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to the occasional treat.
Fast food targets family units. Families have difficulty fitting in all their
desired pursuits so fast foods meet the need for supplying food quickly.
Food is available on demand with many fast -food outlets open late so
consumers do not have to stick to traditional meal times. This also
encourages grazing.
Fast food can also be cheap and easily accessible so cooking skills at home
become devalued.
The fast-food culture has also had an effect on traditional events such as
children’s birthday parties. Parents can now hand over responsibilty to
fast-food restaurants to provide the food and additional entertainments
such as play areas.
Some school lunches are based on a mock fast -food outlet such as a noodle
bar to encourage uptake. Since these must follow the guidelines of
‘Healthy Eating in Schools: a guide to implementing the nut ritional
requirements for food and drink in schools (Scotland) regulations 2008’,
published by the Scottish government, students are assured of a healthy
fast-food option.
Fast food has come to play a dominant role in the provision of food but at the
same time has exerted a negative effect on health, especially that of children.
So what are the implications for children’s health of a diet high in junk
food?
 Many junk foods are of low nutritional value . Children, who have smaller
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appetites, require nutrient-dense diets to ensure they receive a variety of
nutrients. If they don’t a variety of deficiency diseases could result , eg
anaemia.
If consumed only occasionally, junk food may not be harmful to children if
examined in comparison to the child’s diet as a whole.
Many fast foods contain additives, which could lead to hyperactivity.
Fast foods may become addictive, which encourages dependency on these
foods and could result in obesity in later life.
High salt levels in junk foods may increase blood pressur e, which could
lead to a stroke or heart attack. However, individual sachets of seasoning
may be available to control salt intake.
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 High fat levels may contribute to obesity and lead to heart disease in later
life. Large portion sizes are also available , which contain more calories.
 High levels of sugar in these foods may contribute to obesity, tooth decay
or type 2 diabetes in later life. Many fast-food outlets now offer sugar-free
drinks
 Diets high in junk foods tend to be low in fruit and vegetables , which may
mean a low intake of non-starch polysaccarides, increasing the risk of
bowel disorders such as constipation, bowel cancer and diverticulitis, and
a low intake of antioxidant vitamins, increasing the risk of CHD and some
cancers.
 Many fast-food outlets have a wide range of salads, fruit smoothies and
prepared fruits which help increase fruit and vegetables in line with
dietary targets and decrease the desire to snack on fatty/sugary junk foods.
 There is a link between nutrition and mental health. The sugar content of
fizzy drinks on offer in fast-food outlets may raise blood sugar levels to
the level where children’s concentration and moods are affected.
Some fast-food outlets and cafe chains are piloting a government scheme to
display the calorie count on their menus to try to encourage people to make
healthy choices when they are eating out. The fat, sugar and salt contents are
not displayed and this has met with criticism. Some low -calorie snacks, for
example, could be high in salt and this would put consumers at risk of high
blood pressure and heart disease.
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