To improve quality and post harvest preservation

1. Ionising radiations for improving
quality and post-Harvest
preservation of produces
Presented By
SHYAMALA.C
2015604605
Storage Engineering

2. Techniques
Several techniques have been developed for
improving post-harvest shelf-life and quality of fruits
and vegetables.
physical chemical Bio-chemical Biological
agents
Irradiation

3. Techniques of Fruit and Vegetable
Preservation
Physical Method
• Low temperature preservation
• Thermal processing
• Removal of water
• High hydrostatic pressures
Chemical method
• Carbonation
• Preservation by high sugar and acid
• Addition of chemical preservatives
• Fermentation
• Pickling
Biological Method
• Hurdle technology
Irradiation

4. Factors affecting Post-Harvest
Losses
• Abiotic and
• Biotic factors
i)Physiological factor
ii)Biochemical factor
iii)Microbiological factor
iv)Parasitic factor

5. Food irradiation
Definition
Food irradiation (the application of ionizing radiation to food) is a
technology that improves the safety and extends the shelf life of
foods by reducing or eliminating microorganisms and insects.
Like pasteurizing milk and canning fruits and vegetables, irradiation
can make food safer for the consumer.
• It is another physical treatment that can be used after harvest to
reduce disease in some commodities.
• Some commodities are surprisingly tolerant. For example,
strawberries can tolerate the doses of radiation required to
effectively control grey mould caused by Botrgti scinerea.
• The Food and Drug Administration (FDA) is responsible for regulating
the sources of radiation that are used to irradiate food. FDA approves a
source of radiation for use on foods only after it has determined that
irradiating the food is safe.

6. Why Irradiate Food?
• Prevention of Foodborne Illness – irradiation can be used to
effectively eliminate organisms that cause foodborne illness, such
as Salmonella and Escherichia coli (E. coli)
• Preservation – irradiation can be used to destroy or inactivate
organisms that cause spoilage and decomposition and extend the
shelf life of foods
• Control of Insects – irradiation can be used to destroy insects in
or on tropical fruits. Irradiation also decreases the need for other
pest-control practices that may harm the fruit.
• Delay of Sprouting and Ripening – irradiation can be used to
inhibit sprouting (e.g., potatoes) and delay ripening of fruit to
increase longevity.
• Sterilization – irradiation can be used to sterilize foods, which can
then be stored for years without refrigeration. Foods that are
sterilized by irradiation are exposed to substantially higher levels
of treatment than those approved for general use.

7. How Is Food Irradiated?
• Gamma rays are emitted from radioactive forms of the element cobalt
(Cobalt 60) or of the element cesium (Cesium 137).
• X-rays are produced by reflecting a high-energy stream of electrons off a
target substance (usually one of the heavy metals) into food.
• 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.
These energy reacts with cellular constituents to cause injury to plant
cells, insects, micro-organism on or in produce. It breaks DNA strands in
insect or micro-organism cells preventing from growing and reproducing in
produce.
UNITS:
The amount of energy absorbed by a produce is expressed in gray or
kilogray.
1 kilo gray= 100 kilo rads = 1000 joules per kilogram

8. Is Irradiated Food Safe to Eat?
FDA has evaluated the safety of irradiated food for more than
thirty years and has found the process to be safe. The World Health
Organization (WHO), the Centers for Disease Control and Prevention
(CDC) and the U.S. Department of Agriculture (USDA) have also
endorsed the safety of irradiated food.
What Foods Have Been Approved for Irradiation?
FDA has approved a variety of foods for irradiation in the
United States including:
• Fresh Fruits and Vegetables
• Lettuce and Spinach

9. Class Produce Purposes Dosage (kGy)
1 Bulbs, roots, and
tubers
To inhibit sprouting during
storage
0.05-0.15
2 Mushrooms and
asparagus
Delayed growth 0.05-0.15
3 Banana, Mango,
Papaya
Delayed Ripening 0.25-0.50
4 Vegetables Delayed post harvest
diseases developed by
plant pathogens
>1.75
Purposes of Irradiation in fruits and vegetables
• Fresh fruits and vegetables-To delay ripening, Insect disinfestation, shelf-life
extension, Quarantine control
• Cereals and their milled products, nuts, oilseeds, pulses, dried fruits-Insect
disinfection, reduction of microbial load
• Dry vegetables, spices, condiments, dry herbs and herbal teas-Reduction of
pathogenic micro-organism, insect disinfection

10. Irradiation is a treatment given to various fruits and
vegetables to control different post-harvest diseases and
disorders
Crop Control of Disease/disorder/pest Min. dose (kGy)
Apple Scald/ brown core 1.5
Apricot peach nectarine Brown rot 2
Banana Ripening inhibition 0.30-0.35
Lemon Penicillium rot 1.5 -2.0
Mushroom Inhibition of stem growth and cap
opening
2
Orange Penicillium rot 2
Papaya Disinfestation of fruit fly 0.25
Pear Ripening inhibition 2.5
Potato Inhibition of sprouting 0.08-0.15
Strawberry, grape Grey mould 2
Tomato Alternaria rot 3

11. Effect of ionizing radiation on fresh fruits and
vegetables

12. Relative tolerance of fresh fruits and vegetables to
ionizing radiation stress at doses < 1kGy

13. Negative Quality Effects of Irradiation on Produce
• As a consequence of irradiation exposure, produce exhibit
increased rates of respiration and ethylene production. After
irradiation exposure, produce may soften more quickly.
• If dosage is between 2-30 kGy, not viable for use on most produce
items due to unintended adverse consequences of irradiation on
produce quality.
• If dosage is between1-2kGy, used as a hurdle by providing a 1-2
log reduction of human pathogens on produce items.
• Tissue softening: >0.6kGy results in fruits and vegetable tissue softening
due to solubilization of pectin, cellulose, hemicellulose and starch.
• Electrolyte Leakage: due to cell membrane damage, may cause product to
appear excessively moist.
• Produce Respiration & Ethylene production: Irradiation subsequently
increases the rate of produce respiration and ethylene production due to
an irradiation stress response. However, irradiation has been shown to
extend the shelf life of some produce items by reducing sensitivity to the
plant ripening hormone ethylene.

14. • Chilling Injury Symptom development: irradiation may increase
sensitivity to chilling injury symptom development.
• Dosage above 1kGy may induce the following quality defects in
fresh fruits and
• Artichoke : stem pitting
• Avocado : internal browning
• Banana : skin damage
• Corn (sweet) : kernel denting
• Cucumber, summer squash & Peppers: skin yellowing
• Grapes : skin discoloration and stem darkening
• Oranges & Grape fruit: surface blemishes, oil gland swelling, peel pitting
• Lemons & Limes: internal cavities
• Iceburg lettuce & endive: reddish-brown, sunken spotting on leaf mid ribs
Negative Quality Effects of Irradiation on Produce

15. Factors affecting produce irradiation efficacy and
detrimental effects
• Irradiation of fruits and vegetables in a nitrogen atmosphere can
reduce the amount of free radicals produced and thus reduce
injury to produce. However, this may also reduce the efficacy of
the irradiation treatment in killing insects or micro-organisms.
Nutritional quality of irradiated produce
• Irradiation below 1kGy does not significantly reduce the nutritional quality of
produce since only negligible losses of most vitamins may occur.
• Fruits and vegetables are a major source of vitamin C in the human diet and it is
one of the vitamins most susceptible to irradiation –induced losses depending
upon commodity, cultivar, irradiation dose/duration and storage temperature and
duration.
• Water soluble vitamins in order of sensitivity to irradiation degradation: thiamin>
ascorbic acid> pyridoxine> riboflavin> folic acid> cobalamin> nicotinic acid.
• Fat soluble vitamins in order of sensitivity to irradiation degradation: vitamin E>
carotene> vitamin A> vitamin K> vitamin D.

16.  Irradiation treatment for fruits and vegetables is intended to extend storage life,
prevent sprouting in potatoes, and minimize pest infestation.
 Destruction of vitamins may occur when a food is subjected to irradiation,
depending on the sensitivity of the vitamin, the amount of energy to which it is
exposed and the medium that it is in.
 Free radicals, peroxides and carbonyls formed during radiation can react with
vitamins (Kraybill 1982).
Radiation Treatment
 RADAPPERTIZATION (Doses > 10 kGy)
Sterilization of spices and other foods
 RADICIDATION (Doses < 10 kGy)
Pasteurization of cereals, flour, fresh and dried fruits and certain vegetables
 RADURIZATION (Doses < 1 kGy)
Inactivation of food spoilage microorganisms and ex-tension of shelf life for
potatoes and onions
(1 kGy = 100 kliorads which Is approved for fruits and vegetables)
Treatment and Dosage of Irradiation

17. Uses of Irradiation
Produce is exposed to radioisotopes (gamma rays or X-
rays) by a machine, which produces a high-energy
electron beam. This helps in:
• Inhibiting sprouting in tubers, bulbs and root crops.
• Delaying the processes of ripening and senescence in certain
climacteric fruits
• Controlling the growth of pathogens, which cause decay in stored
fruits by combination with hot water dip treatments.
• Disinfestations of insects, which cause spoilage in fresh fruits, dry
fruits and nuts as well as quarantine restrictions in their
international trade, and
• Delaying stem elongation and cap opening in button mushrooms.

18. Potential uses of irradiation
• Inhibition of sprouting of tubers, bulb and root vegetables
• Treatment with ionizing energy 0.05-0.15kGy has been shown to inhibit
sprouting of potato, yam, Jerusalem, artichoke, sweet potato, ginger, sugar
beet, carrot, onion and garlic.
• Inhibition of post harvest growth of Asparagus
• Subjecting asparagus spears to ionizing energy at 0.05-0.15kGy inhibits
their elongation and curvature, but higher doses are detrimental to quality
and storage life.
• Inhibition of post harvest growth of mushrooms
• Ionizing radiation at 0.06-0.5kGy has been shown to inhibit cap opening
and stalk elongation, reduce surface molds and darkening of the gills and
maintain the fresh appearance of mushrooms.
• Insect disinfestation
• Effective insect-disinfestation treatment which are not harmful to the
consumer, the workers, or the commodity are essential for allowing
unrestricted distribution of fresh fruits and vegetables
Adel A.Kader.1986. ‘Potential Application of Ionizing Radiation in Post harvest
Handling of Fresh Fruits and Vegetables’. Food technology.

19. CARROTS
• Shredded carrots were either chlorinated, rinsed and spin-dried as in
industrial processes, or irradiated (2kGy) which replacing the three
steps.
• Several factors like Gas composition inside packed plastic bags, sugar
content, color defining the quality of minimal processed vegetables
were monitored during storage at 10O C.Atmospheres inside micro-
porous plastic bags stabilized at 7-15% O2 and 10-15% CO2.
• Sugar levels in tissues were twice as high in irradiated samples.
• Irradiation also prevented losses of orange color and carotenes.
• Growth of aerobic mesosphilic and lactic microflora was strongly
inhibited by irradiation.
Sensory analysis demonstrated preferences for irradiated
vegetables.
Chervin.C and P.Boisseau,1994. ‘Quality Maintenance of “Ready to eat” shredded
carrots by Gamma Irradiation’. Institute of food technology.59(2):359-362&365

20. Research carried for various fruits
• This article is a summary of 15 years work, and offers an evaluation of
the commercial potential for irradiation of some major California
commodities.
• Gamma rays from cobalt-60 were used in these tests, but the results
would be com- parable with other types of radiation; certainly, the
commercial potential would not change.
• Only one California commodity, strawberries, showed promise for
commercial application of radiation and even with this crop its use
would depend on major changes in marketing conditions.
Textural damage
• Textural damage to flesh and skin from irradiation was so severe that
the resulting processing and shipping quality was unacceptable in
apricots, avocados, cucumbers, nectarines, olives, peaches, peppers,
plums and tomatoes. Visual symptoms of injury quickly appeared in
lemons, lettuce, limes and table grapes.
Maxie.E.C and N.F.Sommer.1970.’Irradiation of California’

21. Irradiation also increased decay in lemons and grapes in storage.
Apples, oranges, and mushrooms were moderately tolerant of
radiation hut with these fruits irradiation was no more beneficial
than cold storage.
Research carried for various fruits

22. Strawberries:
• Irradiation controlled decay of strawberries without adverse
effects on appearance, taste or vitamin content in both laboratory
and simulated transit tests. This report covers the response of
irradiated strawberries to commercial transcontinental
shipments.
Research carried for various fruits

23. Regulatory Issues
FDA regulates the lawful use of irradiation through the food
additive petition process, the completion of which results in the
promulgation of a regulation published in the Federal Register
prescribing the approved use.
• Irradiation as a Food Additives:
Under section 201 of Federal, Food, Drug, and Cosmetic
Act, a source of radiation used to treat food is defined as a food
additive.
• Produce Specific irradiation Rules and Regulation
• The FDA issued a final rule which permits the irradiation of fresh foods
including fruits and vegetables at doses up to 1 kGy for the inhibition of
growth and maturation and for insect disinfestation.
• FDA amended the food additive regulations to provide for the safe use of
ionizing radiation for control of food-borne pathogens, and extension of
shelf-life in fresh iceberg lettuce and fresh spinach at a dose up to 4.0 kGy.

24. • Packaging materials
• Materials used to package produce before irradiation must be accepted for
use by the FDA. Acceptable materials are listed in 21 CFR 179.45
• Labeling
• Retail: irradiated produce sold in retail packages must be labeled with the
radura symbol and contain the statement “Treated with radiation”
• Food Service: for irradiated produce not sold in retail packages, the radura
symbol and the statement must appear on either the individual item, the
bulk container or a sign at the point of purchase.
• Bulk produce for Re-packing or processing: the labeling and invoices of
bills of labeling for products shipped for further processing, labeling or
packaging must bear the statement “Treated with radiation-do not
irridigate again”
Regulatory Issues

25. • But in most of the above cases, the technology of irradiation
finds a limited commercial application as either some
cheaper and more effective alternatives are available or the
treatment leaves undesirable effect on the produce and
cause abnormal ripening.
Disadvantage

26. Thank You