Postharvest Management of
Fruits & Vegetables
VISION
• To add value to fruits and vegetables
in successive stages up to the point
when someone eats them and also
to maximize this added value
• Postharvest handling delays the
death of fruits and vegetables for the
periods as long as possible.
Postharvest Management
• is a set of post-production practices that includes:
cleaning, washing, selection, grading, disinfection,
drying, packing and storage. These steps eliminate
undesirable elements and improve product
appearance, as well as ensuring that the product
complies with established quality standards for fresh
and processed products.
• Postharvest practices include the management and
control of variables such as Temperature and Relative
humidity, the selection and use of packaging, and the
application of such supplementary treatments as
fungicides (FAO 2009 ).
Cont……
• Morphologically and physiologically the fruits and
vegetables are highly variable, may come from a
root, stem, leaf, immature or fully mature and
ripe fruits.
• Botanically many crops, defined as vegetables,
are fruits e.g., tomato, capsicum, melons etc.
• They have variable shelf life and require different
suitable conditions during marketing.
• All fresh horticultural crops are high in water
content and are subjected to desiccation (wilting,
shriveling) and to mechanical injury
Postharvest Losses
• Postharvest operations include at harvest,
handling, transport to a packing facility,
transport technologies and storage to preserve
horticultural products until delivery to a
customer
• Delay in ripening lead to prolonged storage by
preventing fruit tissue respiration
• Total losses amounts for as low as 20% but
approx. 40-50% (Harvest to consumption) in
both developed and developing economies with
the exceptions for greater in developing world
• Lack of basic post harvest technologies and
access to adequate and reliable cooling
contribute to these losses
• In developed economies waste is associated at
the distribution/retail/consumer levels
• Reduction in this wastage/loss, particularly if it
can economically be avoided, would be of
great significance to growers and consumers
alike
Factors Affecting Postharvest Losses
Postharvest losses vary widely from place to place
depending upon the marketing system
 Pre-harvest production practices
 Harvesting and field handling
 Packing or packaging
 Transport
 Market handling; possibly storage or refrigeration
 Perishability of the produce.
•
Pre-harvest Production
Practices
• This may affect marketing of produce in terms of quality
and quantity resulting in rejection or substandard at the
time of its sale due to followings
 Water supply (Irrigation)
 Soil fertility (use of fertilizers)
 Cultivation practices
 Use of agro chemicals (pesticides and herbicides)
Harvesting and Field Handling
 Quality cannot be improved after harvest, only
maintained; therefore it is important to harvest fruits
and vegetables at the proper stage and size and at
peak quality
 Harvest should be completed during the coolest time of
the day, which is usually in the early morning, and
produce should be kept shaded in the field.
 Handle produce gently. Crops destined for storage
should be as free as possible from skin breaks, bruises,
spots, rots, decay, and other deterioration
Cont…..
 Bruises and other mechanical damage not only
affect appearance, inc. rate of respiration but
provide entrance to decay organisms as well.
 Post harvest rots are more prevalent in fruits
and vegetables that are bruised or otherwise
damaged. Mechanical damage also increases
moisture loss
Cont……
 Damage can be prevented by:
 training of harvest labor to handle the crop gently;
 harvesting at proper maturity;
 harvesting dry whenever possible;
 handling each fruit or vegetable no more than
necessary (field pack if possible);
 installing padding inside bulk bins;
 avoiding over or under-packing of containers
PACKAGING
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GAPs IN PACKING HOUSES
Use chlorinated water to wash produce
Change water when dirty
Wash, rinse and sanitize packing lines surfaces at end
of each day
 Store packaging material in a clean area
 PACKING OR PACKAGING
 Suitable packages and handling techniques can reduce
the amount of damage to which fresh produce is
exposed during marketing
 Packaging should be designed to prevent physical
damage to produce, and be easy to handle
Selection of Packaging
• Provide a uniform-size of package to protect the produce
• Can be easily transported when empty
• Must be easy to assemble, fill and close either by hand or by use of
a simple machine
• Must provide adequate ventilation for contents during transport
and storage
• its capacity should be suited to market demands
• its dimensions and design must be suited to the available transport
in order to load neatly and firmly
• it must be cost-effective in relation to the market value of the
commodity for which used
• it must be readily available, preferably from more than one supplier
Packing House Handling
Packing house on the-farm shed or an Automated
regional packaging line handling large tonnages of a
single commercial crop like citrus fruit including:
 selection and grading: manually or on a packing
Sorting: removes foreign matter (stones, leaves,
debris)
 Cleaning and washing: hand washing or on a line
use only clean running water
 Fungicide treatment: post-harvest application of
fungicide is usual on crops such as bananas, yams
and citrus fruit which are to be stored for a long
period or those which undergo long periods of
transport to distant markets.
 Quality selection and grading: manually or on a
packing line
Transportation
• Transportation is a big and often the most important
factor in the marketing of fresh produce
• Ideally, transport would take produce from the grower
directly to the consumer
• Losses directly attributed to transport conditions can
be high
• The goal of every person concerned with transport
should be that the produce be kept in the best possible
condition during transport and that the haulage of
produce be quick and efficient
• To this end, produce should be properly packaged and
properly loaded on a suitable vehicle
• Non-refrigerated transport cause damage/loss
primarily by mechanical damage and by overheating
• Mechanical damage
• careless handling of packed produce during loading
and unloading
• vibration (shaking) of the vehicle, especially on bad
roads
• fast driving and poor condition of the vehicle
• Poor stowing which allow package in transit to sway,
the stow may collapse
• packages stacked too high; the movement of
produce within a package increases in relation to its
height in the stack
.
• Over heating
• This can occur not only from external sources but
also from heat generated by the produce within the
package itself.
• Overheating promotes natural breakdown and decay,
and increases the rate of water loss from produce.
• Causes of Over heating include:
• the use of closed vehicles without ventilation
• close-stow stacking patterns blocking the
movement of air between and through packages,
thus hindering the dispersal of heat
• the lack of adequate ventilation of the packages
themselves
• exposure of the packages to the sun while
awaiting transport or while trucks are queuing to
unload at their destination
• CAUTION
• Fresh produce should not be transported in
vehicles that previously held animals or harmful
substances
• Prior to loading, the trailer must be inspected to
ensure it is clean, in good condition, free from
disagreeable odors and free from dirt and debris.
• Ensure vehicles and containers are clean and
sanitary
• Trucks and trailers should be loaded in a manner
to minimize damage to the product.
Maturity
• Maturity at harvest is the most important factor
that determines postharvest-life and final quality
such as appearance, texture, flavor, nutritive
value
• The level of maturity actually helps in selection of
storage methods, estimation of shelf life,
selection of processing operations for value
addition etc.
• A simple color guide and size can help pickers
harvest produce at the correct stage of
development
Definitions
• Mature: Latin word ‘ Maturus ’ which means
ripen. It is that stage of fruit development, which
ensures attainment of maximum edible quality
at the completion of ripening process
• Maturation: Developmental process by which the
fruit attains maturity. A transient phase of
development from near completion of physical
growth to attainment of physiological maturity.
There are different stages of maturation e.g.
immature, mature, optimally mature, over
mature.
• Ripe: Derived from Saxon word ‘ Ripi ’, which
means gather or reap. This is the condition of
maximum edible quality attained by the fruit
following harvest. Only fruit which becomes
mature before harvest can become ripe
• Ripening: is associated with physical and biochemical irreversible
process which leads to senescence and finally leads to death. A
series of changes occur during early stages of senescence of fruits
in which structure and composition of unripe fruit is so altered that
it becomes acceptable to eat.
• A complex physiological process resulting in softening, coloring,
sweetening and increase in aroma compounds before ready to eat
or process.
• The associated physiological or biochemical changes include
increased rate of respiration and ethylene production, loss of
chlorophyll (but undesirable in vegetables) and continued
expansion of cells and conversion of complex metabolites into
simple molecules.
• Types of indices and their components:
• Visual indices (size, shape and color)
• Physical indices (firmness-Penetrometer and
specific gravity)
• Chemical measurement: Soluble Solids
Content (SSC) or total soluble solids (TSS) and
Titratable acidity (TA)
• Calculated indices: calendar date and heat
units
Maturity Indices
Fruits/vegetables
Maturity indices or characteristics
Apple Golden Delicious’
12 % TSS, 18 lb firmness
Apple Red Delicious’
11 % TSS, 18 lb firmness
Cherry
TSS = 14–15 %, light red color
Grapes (table)
Min TSS % of 14–17.5, depending on
cultivars, TSS/TA of 20 or higher
Guava
Color break stage (when skin color
changes from dark green to light
green
Lemon
30 % or more juice by volume
Litchi
30 % or more juice by volume
Mango
Changes in shape (increase fullness of
cheeks or bulge of shoulder), flesh
color yellow to yellowish-orange
Papaya
Skin shows yellowing
Peach
Ground color change from green to
yellow (varied for different cultivars
Plum
Skin color changes
pomegranate
Minimum 1.85 % TA and red juice color
Strawberry
2/3 of berry surface showing pink or red
color
Peas
Pods well filled but not faded in color
• Fruits picked at less than mature stages are subjected
to greater shriveling and mechanical damage and are
of inferior flavor quality. Overripe fruits are likely to
become soft and/or mealy in texture soon after harvest
and have very limited market life.
• Small or immature vegetables possess better texture
and quality than mature or over-mature vegetables
• However, necessity of shipping mature fruitvegetables long distances has often encouraged
harvesting them at less than ideal maturity, resulting
in suboptimal taste quality to the consumer
Grouping of Fruits & Vegetables on the
basis of Maturity:
• Immature fruit-vegetables- the optimum eating
quality is reached before full maturity and
delayed harvesting results in lower quality at
harvest and faster deterioration rate after
harvest. Normally produce only very small qty. of
ethylene and damaged by exposure to 1 ppm or
higher concns. Examples are green chili pepper,
cucumber, sweet pea, okra etc
• Mature fruit-vegetables-most of the fruits reach peak
eating quality when fully ripened on the plant and,
with the exception of tomato, all are incapable of
continuing their ripening processes once removed from
the plant, produce larger quantities of ethylene in
association with their ripening, and exposure to
ethylene treatment will result in faster and more
uniform ripening as indicated by loss of chlorophyll
(green color), increase of carotenoids (red, yellow, and
orange colors), flesh softening and increased intensity
of characteristic aroma volatiles. Examples are tomato,
red peppers, muskmelons, watermelon
Postharvest Handling
Pre-cooling of horticulture produce
• Affect the shelf life of the produce
• Immediately remove the field heat
Methods of Cooling
• Room cooling: Low cost and slow, circulation of cool air
• Forced air cooling: fastest method, Cool air flow through
vents/holes and time depends on (i) airflow, (ii)
temperature difference between the produce and the cold
air and (iii) produce diameter.
• Hydro-cooling: two types- shower and immersion type,
quick cooling used before packaging because of cost, avoid
water loss
• Vacuum cooling: takes place by water evaporation from the
product at very low air pressure, cause about 1 % produce
weight loss (mostly water) for each 6 C of cooling.
• Package icing: crushed or flaked ice is packed along with
produce for fast cooling
Postharvest Handling
Packing House Operations:
Quality cannot be improved after harvest.
• Minimize mechanical damage-bruises,
• Reduce air temperatures by 8–17 °C (pre-cooling) and all handling should
be in shaded area
• Dumping: immersing produce in water being more gentle or dry dumping
with soft brushes to remove dirt/dust
• Pre-sorting: injured, decayed-to avoid spread of infection , mis-shapen
fruits
• Washing and cleaning: Chlorine solution (100–150 ppm), pH 6.5-7.5
• Sizing/grading: Manually or by automatic grading, round units through
sizing rings. Imp. for local & intrl. mrkt
Postharvest Treatment
Postharvest changes in fresh fruit cannot be stopped, but
these can be slowed down by following operations:
• Washing with chlorine solution – microbial load
• Ethylene inhibitors/Growth regulator/fungicide
treatments: 1-MCP(1-methylcyclopropene), AVG
(Amenoethoxy vinyl glycine), silver nitrate, silver
thiosulfate, cycloheximide, benzothiadiazole etc. are some
of the chemicals which inhibit ethylene production and/or
action during ripening and storage of fruits. The growth
regulators or fungicidal application such as GA 3 can be
effectively used to extend/enhance the shelf life of fruits.
Chemicals that accelerate ripening
• Ethylene: Ethylene related compounds – CEPA-2 Chloro
ethyl phosphoric acid, CPTA-2,4 Chloro phenyl triethyl
amine- used for pre and postharvest treatments
• Acetylene and calcium chloride: Calcium carbide treatment
to generate acetylene to hasten fruit ripening in banana
• Smoke treatment: Burning and releasing smoke from
leaves, twigs or straw will also hasten ripening in mango
• 2,4-D: 2, 4 dichlorophenoxy acetic acid is used in ripening
of Guava
• 2,4,5-T: 2,4,5-trichlorophenoxy acetic acid used in Sapota
Chemicals that delay ripening
• Cytokinins & Kinetins: Delays chlorophyll degradation and senescence of
leafy vegetable
• Gibberellins: Post harvest treatments with GA3 retard ripening of tomato
and bananas, lowers respiratory rate, retards ripening in climacteric fruits
and delays the process of color changes
Growth retardants
• MH – prevents sprouting of onion bulbs and potato tubers. Also delays
ripening of mango
• Alar: Reduce…. Fruit firmness, color development and early maturation. It
is applied before harvest. In lettuce it reduces senescence
• CCC (Cycocel)-2 chloroethyl-trimethyl ammonium chloride used in
delaying of senescence of vegetables.
• Calcium application :CaCl2(2–4%) or Ca (NO3)2 for
5–10 min dip
• delays aging or ripening,
• reduces postharvest decay,
• controls the development of many physiological
disorders
• increases the calcium content, thus improving
their nutritional value,
• reduces chilling injury
• increase disease resistance in stored fruit.
Thermal treatment
(a) Hot water treatment:
dipping in hot water before marketing or storage
to control various post-harvest diseases and
improving peel color of the fruit
(b) Vapor heat treatment (VHT):
control infection of fruit flies after harvest,
exposure to 43 ºC in saturated air for 8 h and
then holding the temperature for further 6 h- it is
mandatory for export of mangoes.
Hot water treatments for different
fruits
Commodity
Pathogen
Temp ( C )
Time
(Minutes)
Apple
Gloeosporium sp., Penicillium
expansum
45
10
Grapefruit
Phytophthora citrophthora
48
3
Lemon
Penicillium digitatum,
Phytophthora sp.
52
5-10
Mango
Collectotrichum gloeosporioides
52
5
Orange
Diplodia sp. Phomopsis sp.
Phytophthora sp.
53
5
Papaya
Fungi
48
20
Peach
Monolinia fructicola,
Rhizopus stolonifer
52
2.5
• Fumigation:
SO2 fumigatim/1 hour) through cylinder or special
sodium metabisulphite pads is used for controlling
post- harvest diseases of grapes, prevent discoloration
of skin of litchis.
• Irradiation:
Ionizing radiation control micro-organisms and inhibit
or prevent cell re-production and some chemical
changes. Applied through radiations from
radioisotopes (normally in the form of gamma-rays
measured in Grays (Gy), where 1 Gy = 100 rads.
Delaying ripening process by skin coating- Waxing:
•
•
•
•
•
•
To replace some of the natural waxes,
Prevents transportation losses and minimize respiration rate,
help reduce water loss during handling and marketing,
Sealing tiny injuries and scratches on surface,
Improves cosmetic appearance and prolongs the storage life
Sugar wax along with emulsifier is melted and then boiling
water is poured slowly to melted ingredients and prepare
emulsion
• The wax coating must be allowed to dry thoroughly before
packing
Emulsifying agents:
• TEA (Triethylene amine), TBZ – Tribenzoate,
fungicides – SOPP (Sodium ortho phenyl
phenate) for control of pencillium in oranges
(Take the emulsion in large basins and dip the
fruit or basket containing fruits for 30 seconds
• Thiourea – is used for control of penicillium
and deplodium on oranges.
Issues of Food Safety
• Unsafe use of pesticide, unregistered material,
higher doses, lack of protective clothing &
training, application close to harvesting and
consumption
• Microbial safety, human hygiene, washing of
hands after using sanitary facilities
• Cool transport, cold storage, improved
insulation, harvesting at coolest time of day,
non-use of plastic bags to reduce water loss
Quality and Nutrition Retention
•
•
•
•
•
•
•
Two important Factors: temperature and water loss
Temperature control (constant temp, well insulated prevent temp
variations- to avoid sweating) through refrigeration retards
deteriorations such as:
aging due to ripening, softening, and textural and color changes
undesirable metabolic changes and respiratory heat production
resulting in decreased food value, loss of flavor, loss of salable
weight, and more rapid deterioration
moisture loss and the wilting
spoilage due to invasion by bacteria, fungi, and yeasts
undesirable growth, such as sprouting of potatoes
Refrigeration controls the crop's respiration rate, higher the storage
temperature, the higher the respiration rate will be
Cont…..
• Temperature has a two-fold effect-govern the rate of
biochemical processes leading to over-ripening and
greater water loss due to warmer environment
• Relative humidity directly influences water loss in
produce, most produce retain better quality at high
relative humidity (80 to 95%), but at this humidity,
disease growth is encouraged
• Vitamin-C may decline when significant water loss
occurs
• Modified atmospheres, however, improve vitamin-C
retention
RH Management

The moisture content (as water vapor) of the atmosphere, expressed as a
percentage of the amount of moisture that can be retained by the
atmosphere at a given temperature and pressure without condensation.

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RH can influence
water loss,
decay development,
incidence of physiological disorders,
uniformity of fruit ripening
•
•
•
Ranges:
Fruits: 85-95% of RH.
Dry products: onion and pumpkin. 70-75% RH.
Root vegetables: carrot, radish. 95-100% RH.
Recommended Storage Temperatures
1-40C (34-390F)
5-90C (41-480F)
>100C (580F)
Apple
Avocado (Temperate)
Avocado (Tropical)
Asparagus
Zucchini
Tomato
Grapes
Egg Plant
Papaya
Mushroom
Cucumber
Mango
Lettuce
Peppers
Pineapple
Peach & Plum
Potato
banana
Berry fruit
Sweet potato
Physiological Characteristics for
Packaging
Non-climacteric fruit:
• Harvested at full ripening (90-95%)
• complete color development.
• Rate of respiration is less than climacteric fruit. Ripen only
while still attached to the parent plant.
• Their eating quality suffers if they are harvested before
they are fully ripe because their sugar and acid contents do
not increase further.
• Respiration rate gradually declines during growth and after
harvesting e.g: cherries, orange, cucumbers, grapes,
lemons, strawberry and pineapples.
• Ethylene levels usually range from 0.1 to 0.5 ppm/(kg h)
during ripening
Climacteric fruit:
• Harvested at full maturity stage
• Ripen after harvest.
• Maximum respiration starts immediately after harvest.
• Long shelf life (6-8 days) no need of sophisticated packing material
as fruits are hard
• Fruits may undergo either natural or artificial ripening.
• The onset of ripening is accompanied by a rapid rise in respiration
rate, generally referred to as the respiratory climacteric.
• After the climacteric, the respiration rate slows down as the fruit
ripens and develops good eating quality e.g: apples, bananas,
melons, papaya and tomatoes, avocado. Ethylene evolution can
reach 30-500 ppm/(kg h)
Packaging Objectives
• Contain product and facilitate handling and
marketing by standardizing the number of units
or weight inside the package.
• Protect product from injuries and adverse
environmental conditions during transport,
storage and marketing.
• Provide information to buyers, such as variety,
weight, number of units, selection or quality
grade, producer’s name, country and area of
origin.
Storage Solutions
• Access to refrigeration to control the respiration rate
• Ethylene control (either treatment with or methods
to remove)
• Ethylene action inhibition (1-methylcyclo-propene)
• Modified atmosphere packaging
• Controlled atmosphere storage
• Do not store different product in same storage area
due to adverse effects on shelf-life and quality
• Controlled atmosphere transport trailers
• Waxes and other surface coatings which restrict the
gases interchange
• Postharvest disease and insect control
• Novel packaging innovations for storage at slightly
higher temperatures
• Genetic modification-production of hybrids and
varieties with high contents of carotenes, vitamins,
sugars and ascorbic acid
• judicious dose of γ-irradiation (0.1–0.5 kGy)
• Utilization of unmarketable/physically damaged
produce but without infection for conversion to value
added products and their bye-products
Controlled Atmosphere/Modified
Atmosphere Storage
• Involves adjustment of the atmospheric composition
surrounding commodities by removal (mainly O2) or
addition (mainly CO2) of gases from the environment
surrounding the fruits and vegetables against normal air
with 79% N, 21% O2 and traces CO2.
• MA (2% - 5% O2 & 8% - 12% CO2) concentrations of the
gases are less precisely controlled against CA.
• Use of MA during packing is highly increasing.
• Basic requirements for CA storage include a gas tight
chamber and control of the concentrations of CO2 and O2.
• When combined with refrigeration, CA markedly enhances
the shelf life of fruits and vegetables
MAP
• Modify the concentration of gases in surroundings of the
produce.
• MA Package material is impregnated with minerals in order to
absorb and remove ethylene production,
• use of Condensation Control Packaging (CCP) and compact
controlled atmosphere packaging (CCAP).
• Reduce respiration rate: by avoiding mechanical damage,
sanitary condition, temp- 10 degree rise give 2 to 3 fold inc.,
(< Oxygen and CO2< respiration), by application of waxes
• Reduce ethylene action: leafy vegetable sensitive to ethylene.
; > ethylene > respiration
• Delay ripening & senescence.
• Increase product’s shelf life.
Advantages of MAP Packaged
produce in CA storage
• Quality of internal & external color and flesh
maintained;
• Reduced chilling injury;
• Delayed ripening and senescence;
• Texture of fruit maintained;
• Shelf life of fruit increased, and the frequency
of delivery reduced;
• Reduced decay and weight loss.
Maximum Storage Life (Days)
Commodity
Normal
Atmosphere
Controlled
Atmosphere
Low-pressure
storage
Apple
200
300
300
Asparagus
14-21
Slight benefit-off
odor
28-42
Avocado
30
42-60
102
Banana
14-21
42-46
150
Mango (Haden)
14-21
No benefit
42
Pear (Bartlett)
60
100
200
Tomato (Mature
Green)
7-21
42
84
Minimal Processing
• An integrated approach wherein the handling,
processing, packaging and distribution of raw
fruits and vegetables is properly managed with
the application of appropriate food safety
principles of Good Manufacturing Practices
(GMP)and Hazard Analysis and Critical Control
Point (HACCP).
• Microorganisms are inhibited by combined
preservative factors (referred to as hurdles such
as sorbate, benzoate, and ascorbic acid)
Cont……
along with low temperature storage, mild heat
treatments, control of water activity, control of
redox potential through appropriate packaging
• Non-Thermal Processing Technologies
High intensity pulsed electric fields
High intensity pulsed light
High hydrostatic pressure
Food irradiation
High Intensity Pulsed Electric Fields
• PEF technology is the application of short pulses of high
electric fields with duration of microseconds micro- to
milliseconds and intensity in the order of 10-80 kV/cm
• The processing time is calculated by multiplying the
number of pulses times with effective pulse duration. The
process is based on pulsed electrical currents delivered to
a product placed between a set of electrodes; the distance
between electrodes is termed as the treatment gap of the
PEF chamber
• It is suitable for preserving liquid and semi-liquid foods
removing micro-organisms and producing functional
constituents. Examples:- milk, fruit juices, soup, egg etc.
High Hydrostatic Pressure
• HP unit consists of a cylindrical pressure vessel, a pressure
generator, a temperature control device, and a pressure
handling system.
• HP processing is conducted in a closed system (batch),
however, multiple closed system vessels can be used to
maintain the production continuity (semi-continuous).
• A pressure-transmitting medium (water, oil or water/oil
mixture) is pumped to the pressure vessel using a pressure
intensifier to reach the desired pressure level and
afterwards, the pressure is isolated in the vessel.
• From this moment, the processing time is counted and
stopped by releasing pressure. The whole HP processing
cycle normally has a duration of minutes
High Intensity Pulsed Light
• Rapid and effective low thermal, low energy
purification and sterilization technique
• Very high powered short duration light pulses
emitted by inert gas flash lamps
• Limited to treatments of very transparent
foods, surface treatments and for food
packaging’s.
• It cannot be used for solid foods
Food Irradiation
Ionizing radiation in food processing is based mainly on the
fact that:
• It damage very effectively the DNA so that living cells
become inactivated, therefore microorganisms, insect
gametes, and plant meristems are prevented from
reproducing
• Result in various preservative effects as a function of the
absorbed radiation dose. At the same time, radiationinduced other chemical changes in food are minimal
• Irradiation technology proved to be effective in reducing
post-harvest losses, and controlling the stored product
insects and the microorganisms
Cont……
There are three sources of radiation approved for use on foods.
• Gamma rays are emitted from radioactive forms of the
element cobalt (Cobalt 60) or of the element cesium (Cesium
137). Gamma radiation is used routinely to sterilize medical,
dental and household products and is also used for the
radiation treatment of cancer.
• X-rays are produced by reflecting a high-energy stream of
electrons off a target substance (usually one of the heavy
metals) into food. X-rays are also widely used in medicine and
industry to produce images of internal structures.
• Electron beam (or e-beam) is similar to X-rays and is a stream
of high-energy electrons propelled from an electron
accelerator into food.
Fresh-Cut-Produce
• No thermal or other preservation treatment, HACCP-reduction of
bacterial pathogen
• Chlorinated water (200 ppm max.) to reduce microbial population
Constraints
• From biological and food-safety perspectives, fresh-cut fruit is
different from fresh-cut vegetables.
• Low-acid fruit will have food-safety challenges different from those
of high-acid fruit,
• Leafy vegetables will have challenges different from those of fleshy
vegetables
• Distinct variations in the physiology, biochemistry, and microbiology
of the many food systems in fresh-cut produce,
Key Factors for Quality & Shelf-life
• Cultivar Selection: flesh texture, skin color, browning potential,
chilling sensitivities, and flavors
• Ripeness stage at cutting
• Firmness and size of raw materials,
• Preprocessing conditions (such as fresh or storage),
• Storage temperature, storage atmosphere, storage duration, and
growing conditions
• Effect of ethylene complexity
• Chilling Injuries during refrigerated storage at 0 to 10°C
• Oxidative browning: Ascorbate is a very effective browning
inhibitor for fresh-cut apples, vacuum packing, however, off-odor
formation during inappropriate package selection and storage
temperature and thus reduce the shelf-life.
Storage Tips
• Store only high quality produce, free of damage,
decay and of proper maturity (not over-ripe or
under-mature).
• Know the requirements for the commodities you
want to put into storage, and follow
recommendations for proper temperature,
relative humidity and ventilation.
• Avoid lower than recommended temperatures in
storage, because many commodities are
susceptible to damage from freezing or chilling
• Do not over load storage rooms or stack containers
closely
• Provide adequate ventilation in the storage room.
• Keep storage rooms clean.
• Storage facilities should be protected from rodents by
keeping the immediate outdoor area clean, and free
from trash and weeds.
• Containers must be well ventilated and strong enough
to with stand stacking. Do not stack containers beyond
their stacking strength
• Don’t store onion or garlic in high humidity
environments
• Monitor temperature in the storage room by
placing thermometers at different locations.
• Avoid storing ethylene sensitive commodities
with those that produce ethylene.
• Avoid storing produce known for emitting strong
odors (apples, garlic, onions, turnips, cabbages,
and potatoes) with odor-absorbing commodities.
• Inspect stored produce regularly for signs of
injury, water loss, damage and disease.
• Remove damaged or diseased produce to prevent
the spread of problems