Uploaded by Musembi Ndeto

Food Contamination

advertisement
FOOD CONTAMINATION
Food contamination refers to when something gets into food that shouldn't be there, thereby
making the food unsafe to eat.
While there are many food safety hazards that can cause food contamination, most fall into
one of three categories: biological, physical or chemical contamination. In many cases, a
single hazard can introduce more than one type of contamination to food.
Types of food contamination
BIOLOGICAL CONTAMINATION
Biological contamination occurs when food becomes contaminated by living organisms or
the substances they produce. This includes biological matter produced by humans, rodents,
insects and microorganisms. Biological contamination is the leading cause of food-borne
illness and food poisoning*, and a common cause of food spoilage and food waste.
There are six types of microorganisms that can cause food-borne illness: bacteria, viruses,
parasites, protozoa, fungi and prions.
Most food-borne illnesses in Canada are caused by bacteria or viruses, with the most
common being:

Norovirus

Listeria

Salmonella

E. coli

Campylobacter
Food-borne illness occurs when disease-causing microorganisms, also called pathogens,
get into food and multiply to unsafe levels before being eaten. This can happen remarkably
quickly; in conditions ideal for bacterial growth, one single-cell bacteria can become two
million in just seven hours.
Bacteria and other pathogens thrive in foods that are:

moist

high in protein or starch

neutral in acidity
Foods that meet these criteria are called potentially hazardous or high-risk foods. All highrisk foods are teeming with pathogens and other bacteria; it is your responsibility to stop
bacteria from multiplying to unsafe levels and, where possible, to destroy them via the
cooking process.
To slow down the growth of bacteria and prevent food safety risks, you need to follow food
safety best practices designed to control bacterial growth through proper food handling
techniques, rigorous cleaning and sanitizing procedures and time and temperature control
of food.
Food poisoning occurs when specific toxins are consumed, such as those produced by
Salmonella, Staphylococcus or Listeria; microbial toxins are extremely potent toxins that
can disable the immune system and damage tissues if they are consumed. Many microbial
toxins are heat-resistant, so even if bacteria are destroyed in the cooking process, the
toxins remain in the food and can cause violent, almost-instantaneous symptoms.
To minimize the risk of biological food contamination occurring in your food business,
always:

keep high-risk foods (e.g. meat, poultry, dairy, eggs) out of the Temperature Danger
Zone**

purchase, store, thaw, prepare, cook and serve high-risk foods properly

regularly clean and sanitize all food contact surfaces and equipment

maintain good overall hygiene and sanitation of the premises

maintain high standards of personal hygiene (and ensure all employees do the same)
*The terms “food-borne illness” and “food poisoning” differ slightly in meaning but are often
used interchangeably to describe any food-related illness caused by microorganisms or
their byproducts.
PHYSICAL CONTAMINATION
Physical contamination occurs when a physical object enters food at some stage of the
production or preparation process. Physical objects in food can be a choking hazard and
often introduce biological contaminants as well. Even if the object is not likely to injure your
customer, finding an object in their food can be very distressing for a customer (who knows
that harmful microorganisms on the object could make them ill).
Common examples of physical contaminants in food businesses include:

hair

fingernails

bandages

jewellery

broken glass, staples

plastic wrap/packaging

dirt from unwashed fruit and vegetables

pests/pest droppings/rodent hair
To minimize the risk of physical food contamination occurring in your food business, always:

wear hair neatly tied back or wear a hair/beard net

keep jewellery to a minimum

when necessary, wear brightly coloured bandages that can be easily seen if they fall
off

throw out and replace cracked, chipped or broken dishware, glassware and equipment

use a plastic or metal scoop for ice (never use the glass!)

wash fruits and vegetables thoroughly

establish pest prevention and control procedures as part of your Food Safety Plan
CHEMICAL CONTAMINATION
Chemical contamination occurs when food comes into contact with or produces toxic
chemicals, which can lead to chemical food poisoning. Chemical contaminants fall into one
of two categories: natural and artificial.
Common chemical contaminants include:

cleaning products (e.g. detergent, sanitizer)

pesticides/herbicides

toxic chemicals in metals and plastic

preservatives

naturally occurring toxins
Naturally occurring toxins are toxic compounds that are produced by living organisms, some
of which are staples of the human diet (e.g. shellfish, potatoes, fish). These toxins are not
harmful to the organisms themselves but can be harmful to us if we eat them.
Minimal contamination with natural toxins might not lead to illness, but Food Handlers
should be aware of which foods produce toxins and take all reasonable precautions to
ensure that food is safe for consumption. Potatoes, for example, produce glycoalkaloids that
are toxic to humans. The majority of these toxins are contained in or just under the peel,
and in any eyes or sprouts on the potato. Green skin can indicate the presence of toxins, so
be sure to remove any eyes, sprouts or green skin if you decide to use potatoes that have
greened or sprouted.
There are many ways that food can become contaminated by artificial/synthetic chemicals
in a commercial kitchen. Food Handlers can accidentally cause chemical contamination if
they:

don't store cleaning products and other chemicals properly

use too much detergent or sanitizer to clean food preparation surfaces, glassware,
dishes or cutlery (follow the manufacturer's instructions!)

don't rinse surfaces, glassware, dishes or cutlery properly after cleaning and sanitizing
(if applicable)

don't properly wash fruits and vegetables to remove pesticides

use kitchen equipment or containers made from materials that are not suitable for food
or not designed to be reused (use only food-grade plastic and metals)

use pest control products (e.g. spray, poisonous bait) improperly
To minimize the risk of chemical contamination occurring in your food business, always:

label and store chemicals separately from food

use the appropriate chemical for the job you're doing

follow the chemical manufacturer's instructions with regards to dilution, contact time
and water temperature

use chemical pest control products with extreme care or outsource pest eradication to
a professional pest control service
CROSS-CONTAMINATION
Cross-contamination is the accidental transfer of contaminants from one surface
or substance to another, usually as a result of improper handling procedures. In a food
setting, the term refers to the transfer of contaminants from a surface, object or person to
food. Cross-contamination usually refers to biological contamination but can also be
physical or chemical.
Cross-contamination in a food business often occurs as a result of:

Food Handlers (e.g. microorganisms from sweat, sneezing/coughing, hands, hair,
clothing)

improper food handling techniques (e.g. reusing cutting boards or utensils for raw and
cooked food or for different types of food)

improper cleaning and sanitizing (e.g. not properly rinsing cleaning chemicals from
preparation surfaces, dishware, glassware or equipment)

improper food storage (e.g. storing raw meat on shelves above ready-to-eat food)

improper waste disposal (e.g. allowing garbage containers to overflow)

pests
Cross-contamination can also pose a risk to customers with food allergies, as trace
amounts of an allergen can be transferred in the same way that microorganisms can. Even
trace amounts of an allergen can cause a serious allergic reaction — in some cases, a
lethal reaction. As a food business owner, manager or employee, it is your responsibility to
serve customers a safe meal, including customers with food allergies.
To minimize the risk of cross-contamination occurring in your food business, always:

move around the business in accordance with the Food Safety Plan (e.g. change
soiled kitchen clothing before moving from raw food to ready-to-eat prep stations)

cover and store raw food on shelves below cooked or ready-to-eat food in the
refrigerator

use separate equipment or utensils to prepare raw and cooked foods

use separate equipment or utensils to prepare different types of foods

prepare allergen-free meals separately

establish allergen management procedures as part of your Food Safety Plan

maintain high standards of personal hygiene

wash hands frequently using the correct hand washing technique

handle and dispose of food scraps and waste properly (e.g. ensure garbage
containers are sealed and stored away from food)
Pests deserve a special mention in this regard, as they are notorious sources of crosscontamination in food businesses. Rodents, flies and cockroaches carry untold numbers of
disease-causing bacteria and other pathogens on their bodies, in their droppings and in
urine and saliva, including Salmonella, E. coli and Listeria.
As such, pest prevention and control is vitally important in the workplace. Download
the CIFS Guide to Pest Prevention and Control to find out more about the risks that
common pests pose to a food business, how to prevent pests from entering your business
and what to do if they get in.
In this article













What is Food Contamination?
The Impact of Food Contamination
Types of Food Contamination
Avoiding Chemical Contamination
Physical Contamination
Microbial Contamination
High Risk Foods
What is the Danger Zone Temperature?
Avoiding Microbial Contamination
Allergenic Contamination
Avoiding Allergen Contamination
Preventing Food Contamination
Summary
Food contamination is a global safety concern, with 1 in 10 people falling ill each year due to
eating food that has been contaminated. As a result, businesses are obligated to ensure they
uphold the highest standards of food safety.
A failure to ensure that all food products are safe for consumption could have a catastrophic
impact.
A contaminant is any substance that has been added to food that should not be there. Food can be
accidentally or intentionally contaminated, with contaminated food posing a serious risk to the
consumer. This guide will explore the different types of contamination and how they are likely to
occur. The four main types of food contamination are chemical, microbial, physical, and
allergen, and we will discuss these further. We will also answer questions such as, what are the
types of contamination, and how can you prevent food from becoming contaminated?
Throughout this article, we will also refer to current UK guidance and the relevant food safety
standards.
What is Food Contamination?
Ultimately, food contamination is when something gets into food that should not be there.
Contamination can happen anywhere where the food is being handled or at any stage of the
manufacturing process. However, the main vulnerabilities are in the production and supply
chain.
Many scenarios could result in contamination, and a single case can have long-lasting
ramifications to your business. It is not always obvious whether food has been contaminated. For
example, food that has been contaminated with chemicals or bacteria may not look or taste any
different to food that has not.
Accidental and Intentional Contamination
There are two different types of food contamination, accidental and intentional.
Accidental: Accidental contamination results from unintentional human actions, unexpected
events, and human error. This could also include machinery or equipment breaking, like a piece
of plastic getting mixed into a cake or metal shavings from a broken machine part. It may also be
because of improper handling procedures. As people may be aware of the incident taking place,
accidental contamination is more likely to be dealt with before the product hits the market.
However, even if the item has not reached customers yet, a risk assessment will still need to be
conducted.
Intentional: Also known as food fraud, intentional contamination is a growing concern. It refers
to deliberate acts of contamination, and it is a criminal act. This can occur at any point, and the
perpetrator could be anyone from a stranger to an employee.
The Impact of Food Contamination
In the modern globalised world, food contamination can have far-reaching impacts on the lives
of the people it affects. A report by the World Health Organisation (WHO) stated that:
‘Food contamination that occurs in one place may affect the health of consumers living on
the other side of the planet’.
In the UK, all businesses must adhere to food safety responsibilities as outlined by the Food
Standards Agency. If a business is aware that food has been contaminated and it is unsafe, they
will need to do a product recall. Product recalls are a costly business. They involve a crisis team,
the removal of the product, a full investigation, and money spent on public relations. As well as
being expensive, they can damage public opinion and affect consumer trust. However, a failure
to recall products could have worse consequences.
In recent years, the number of product recalls by companies has increased rapidly. However,
despite some growing fears, not all of these were conducted ‘just in case’. Statistics also show
there has been a dramatic increase in the number of cases of food contamination. Food
contamination can ultimately result in serious consequences. Physical contamination could pose
as a choking risk, high levels of chemicals in food could cause fatalities or long-term illness, and
microbial contamination could cause food-borne illness. For most people, food poisoning does
not have long-lasting effects. However, each year around 600 million people around the world
are ill because of food-borne illness. Furthermore, 33 million people die due to some form of
food poisoning each year. Consequentially, UK businesses that fail to comply with standards are
appropriately penalised.
Types of Food Contamination
There is some dispute regarding how many different types of food contamination there are, with
some saying there are three and others declaring four. Both cover the multiple incidences that
could occur. The three types of contamination are biological, physical, and chemical. However,
for the purpose of this article, we will discuss four categories. These include chemical
contamination, physical contamination, microbial contamination, and allergen contamination.
Chemical Contamination
Chemical contamination is when the food becomes contaminated by some form of chemical. It is
the most difficult type of contamination to control, and it could potentially result in acute
poisoning and long-term diseases. Symptoms of chemical contamination can range drastically. In
most cases, the consumer will experience some form of mild gastroenteritis, but in some
situations, chemicals in food can be lethal.
In recent years, there has been a wider interest in the impact of chemicals in our food and the
potential effects on consumer health and wellbeing. For example, studies have shown that
prolonged exposure to low levels of carcinogens can increase a person’s likelihood of being
diagnosed with cancer.
Natural and Artificial Contamination
There are two different types of chemical contamination, natural and artificial.
Natural chemical contamination refers to the existence of chemicals that occur naturally in
food. These are regulated, and the government has prescribed minimum limits for those
considered harmful. Thus, food production and manufacturing businesses have a responsibility to
ensure there are measures in place to prevent products from exceeding these limits.
Artificial chemical contamination results from food being contaminated with a chemical that is
not a natural by-product of the food. This could include chemicals used for cleaning and
disinfection, fertilisers, and pesticides, amongst others.
Most Common Types of Chemical Contamination
Some of the most common examples of chemical contamination include:








Cleaning products and disinfectants.
Unwashed fruit and vegetables.
Chemicals from the use of non-safe plastics.
Pest control chemicals.
Antibiotics.
Anti-inflammatory drugs.
Corticosteroids.
Heavy metals.
Avoiding Chemical Contamination
Some of the best ways to prevent chemical contamination from occurring include:





Always store chemicals separately from food, including cleaning products.
Always keep food covered whenever possible.
Make sure chemicals are properly labelled.
Do not use poison in the same room as food is manufactured or prepared.
Use utensils resistant to acid and salts.
Physical Contamination
Physical contamination refers to food that has been contaminated by a foreign object. Finding
random objects in our food is certainly off-putting, and it is definitely something that causes
concern for consumers. Food that has been contaminated by a physical object could directly pose
as a choking risk and cause serious injury. Furthermore, the object may also carry bacteria,
which could cause microbial contamination at the same time.
The most common objects to contaminate food include glass, hair, metal, jewellery, dirt, and
fingernails. Physical contamination of food may also be from the environment including the
building and the equipment you are using, such as plaster, flakes of paint, and screw fixings.
Moreover, physical contamination could also occur because of issues with packaging, such as
staples, string, polythene, and cardboard. However, some physical contamination can occur
naturally, like insects entering fruit and vegetables or bones in boneless fish. However,
regardless of whether it is a natural component of the food, businesses must still find out how it
got there and how to avoid reoccurrence of the incidents.
Avoiding Physical Contamination of Food
Physical contamination of food is a global safety concern, and product recalls can cost millions,
as well as damaging the company’s reputation. As a result, businesses have a responsibility to
prioritise customer safety and it is important that they do their utmost to prevent physical
contamination. Some ways of avoiding it include:









Take products out of delivery packaging and store in food-safe containers.
Have a no glass policy in place to prevent the risk of broken glass contaminating the food.
Plasters should be bright blue, so we can easily see them if dropped.
Keep the premises maintained to prevent environmental hazards.
All ingredients used should be washed thoroughly to remove hazards.
Hair should be tied back, with a hair and beard net where possible.
Workers should wear gloves when handling food.
Fingernails should be clean, short and unpolished, with no long or false nails.
Staff should not wear jewellery. However, most companies permit staff to wear a simple
wedding ring.
Microbial Contamination
Microbial contamination, also known as biological, is the most common cause of food poisoning.
It is basically the existence of harmful pathogens in food, like microorganisms, bacteria, viruses,
mould, fungi, and toxins. This is the leading cause of food-borne illness and food poisoning, and
food spoilage or waste is the most common cause of it. Chilling food causes the pathogens to
become dormant but does not necessarily prevent the growth of bacteria. To ensure bacteria are
destroyed during the cooking process, foods should be cooked thoroughly to the right
temperature. However, it is noted that many microbial toxins are heat resistant and spoiled food
should not be cooked and consumed. The most common food-borne illnesses include norovirus,
salmonella, listeria, e.coli, and campylobacter, and symptoms can range from mild gastro issues
to fatal and long-term diseases.
Microbial contamination can occur due to either direct or cross-contamination. Direct
contamination is a result of the pathogens already produced in the food reaching unsafe levels.
An example of this would include the bacteria and toxins found in spoiled meat. Whereas crosscontamination is when pathogens enter food from other sources and multiply to unsafe levels.
High Risk Foods
Some foods are considered to be a high risk of microbial contamination. The nature of these
foods particularly provides an environment in which bacteria can thrive, with the provision of
food, water, and neutral acidity. Some examples of these are:








Meat.
Poultry.
Rice.
Dairy products.
Cooked and raw eggs.
Seafood.
Unpasteurised juices.
Prepared fruits and vegetables.
What is the Danger Zone Temperature?
The danger zone is anything between 5°C and 63°C, with food kept at these temperatures being
particularly prone to microbial contamination. In such ideal conditions, bacteria double their
numbers every 20 minutes. This means that one cell of bacteria can become 2 million in just
seven hours.
Avoiding Microbial Contamination
Some tips for avoiding this type of food contamination include:








Use a thermometer to ensure food is thoroughly cooked.
Raw meat should always be stored separately to cooked meat.
All equipment and utensils should be washed and cleaned regularly.
Food should be covered at all times.
Respect use-by dates.
Fruits and vegetables should always be washed thoroughly.
Food handlers need to always practice excellent hygiene. This includes washing hands regularly,
and after coughing, sneezing, or touching their hair or face.
Regularly check the temperatures of refrigerators and freezers.
Allergenic Contamination
A food allergy is due to the way the body reacts to a specific food, with the body’s defence
system perceiving the substance to be a threat. In the UK, around 5,500 people attend the
hospital per year due to an allergic reaction, a figure which has been increasing since the 1980s.
In fact, in the 20 years before 2012, the UK had seen a 615% increase in the number of people
being admitted in hospital with anaphylaxis. This refers to an acute life-threatening reaction,
during which the body releases histamine to attack the allergen. A person experiencing
anaphylaxis will require emergency medical attention, and it can be fatal.
All businesses that produce food have a responsibility to be aware of the dangers of crosscontamination as even trace amounts of an allergen can cause such a severe reaction. As a result,
strict laws are surrounding this, which businesses must adhere with to ensure customer safety.
Companies must ensure that they have a strict system in place to prevent cross-contamination of
the 14 main allergens.
Cross-contamination can occur at any stage, including during primary food production, harvest,
slaughter, secondary food production, transportation, storage, distribution, preparation, and
serving. Due to the nature of the business, some manufacturers cannot prevent trace
contaminants of allergens contaminating the food. If reasonable adjustments cannot be made,
they will need to add a precautionary allergen statement to their labels; for example, ‘May
Contain Nuts’.
14 Main Allergens
Any foods can trigger an allergic reaction, but some of these are considered to be more
dangerous than others. The 14 different allergens must be clearly marked and labelled. These
include: nuts, peanuts, eggs, milk and dairy, crustaceans, molluscs, cereals containing gluten,
celery, lupin, mustard, sesame seeds, soya, and sulphur dioxide (when added and over 10 mg per
kg).
Avoiding Allergen Contamination
Businesses must take appropriate measures and have a system in place to prevent crosscontamination of allergens. Some steps could include:






All foods should be clearly labelled if they contain the 14 allergens discussed above.
Hands should be washed frequently and properly.
Thoroughly wash all equipment after each use.
Use separate equipment for food products that contain allergens.
Take swabs to test for the existence of allergens.
Store food containing allergens separately, with storage containers clearly labelled.
Preventing Food Contamination
Some of the best ways to prevent contamination involve:
Hygiene: In all aspects of food prep and manufacturing, cleanliness is essential, and all surfaces
and equipment should be cleaned thoroughly. Personal hygiene is also important. Food handlers
should wash their hands regularly and wear gloves and a hair/beard net to prevent physical
contamination.
Storage: Food must be stored properly to prevent contamination during this stage. It should be
covered and in containers that are clearly labelled. Chilled foods should not be left at room
temperature. Furthermore, refrigerators should be between 1°C and 4°C and commercial freezers
should be below -23°C.
Maintenance: In order to prevent physical contamination, maintenance of the premises and
equipment is also essential. Things that are broken should be fixed promptly and recorded
appropriately.
Food preparation: Care must be taken during the preparation and cooking of food to prevent
contamination. Food must always be cooked to the correct temperature, and you should use
different equipment and utensils for cutting and preparing raw meat.
Staff training: To prevent the risk of contamination, businesses are responsible for ensuring
staff have received appropriate training regarding food safety and handling.
Quality control and testing: Accidents happen and mistakes can occur, which is why quality
control and testing is one of the most important stages in manufacturing. Businesses should also
have a strong tracking system. They should know where the product has come from, where it
went, and where it ended up.
Download