Food irradiation is a process that exposes food to ionizing radiation like gamma rays, x-rays, or electron beams to kill microorganisms, bacteria, viruses, or insects that may be present in foods. This helps preserve foods by reducing food loss, extending shelf life, and improving food safety by reducing pathogens. Common foods irradiated include wheat, potatoes, pork, fruits and vegetables, herbs and spices, and meat and poultry. While irradiation helps food preservation and public health, there are some concerns about potential effects on food quality and packaging materials when foods are irradiated in plastic containers. With proper controls and packaging, food irradiation is considered a safe process.

1. FOOD IRRADIATION
SUBMITTEDBY – SAIJJALSURI

2. WHY DO WE PRESERVE FOOD ?
• THE LEVEL OF FOOD LOSS IS HIGH (MORE THAN 40% FOR FRUITS AND VEGETABLES AND MORE FOR FISH
AND MEAT).
• ACCORDING TO THE UNITED NATIONS, MORE THAN 30% OF THE MORTALITY RATE WORLD WIDE IS
CAUSED BY ALIMENTARY DISEASES.
• SOME AGRICULTURAL PRODUCTS ARE IMPORTANT COMMODITIES IN INTERNATIONAL TRADE
(INFESTATION OF SEVERAL SPECIES BY INSECTS AND MITES).
• THE PRESENCE OF PARASITES, SOME MICROORGANISMS, PARASITES AND MOULDS ARE ALSO THE
SOURCE OF PROBLEMS (TOXIN PROBLEMS).

3. WHAT IS FOOD IRRADIATION ?
• PHYSICAL TREATMENTS THAT CONSIST OF EXPOSING FOODS PRE-PACKED OR IN BULK TO THE DIRECT
ACTION OF ELECTRONIC , ELECTROMAGNETIC RAYS TO DESTROY MICROORGANISMS, BACTERIA, VIRUSES
OR INSECTS THAT MIGHT BE PRESENT IN FOODS.
• WHEN MADE TO BOMBARD AGAINST MATERIALS, THEY CAN KNOCK OFF AN ELECTRON FROM AN ATOM OR
MOLECULE CAUSING IONIZATION.
• FOR THIS REASON, THEY ARE OFTEN CALLED IONIZING IRRADIATION.
• THE X-RAYS AND GAMMA RAY ARE VERY SHORT WAVELENGTHS RADIATIONS THAT HAVE VERY HIGH
ASSOCIATED ENERGY LEVELS.

4. SOURCES OF IRRADIATION
1) GAMMA RAYS-
• COBALT-60 – THE CHOICE OF SOURCE OF GAMMA RAYS
• HIGHLY PENETRATING AND CAN BE USED TO TREAT FULL BOXES OF FRESH OR FROZEN
FOODS.
2) ELECTRON BEAMS –
• STREAMS OF HIGH ENERGY ELECTRONS PROPELLED FROM AN ELECTRON GUN.
• SINCE ELECTRONS CANNOT PENETRATE VERY FAR INTO THE FOOD, AS COMPARED TO X-RAYS
OR GAMMA RAYS, THEY CAN BE USED ONLY FOR THIN PACKAGES OF FOOD.
3) X-RAYS –
• BEAM OF ACCELERATED ELECTRONS IS DIRECTED AT A THIN PLATE OF GOLD , PRODUCING A
STREAM OF X-RAYS EXCITING FROM OTHER SIDE.
• HIGH PENETRATING POWER.

5. WHICH FOODS ARE IRRADIATED ?
• WHEAT FLOUR – CONTROL OF MOULDS
• WHITE POTATOES – INHIBIT SPROUTING
• PORK – KILL TRICHINAE PARASITE
• FRUITS AND VEGETABLES – INSECT CONTROL ; INCREASE SHELF LIFE
• HERBS AND SPICES – STERILIZATION
• POULTRY- BACTERIAL PATHOGEN REDUCTION
• MEAT – BACTERIAL PATHOGEN REDUCTION

6. SCOPE OF FOOD IRRADIATION
1) DISINFESTATION–
• IRRADIATION IS AN EFFECTIVE ALTERNATIVE FOR FUMIGATION FOR INSECT CONTROL.
• A COMBINATION TREATMENT OF LOW DOSES OF GAMMA RAYS AND HEAT WOULD BE ADVANTAGEOUS
FOR COMPLETE KILLING OF INSECTS.
2) SHELF LIFE EXTENSION –
• A VERY LOW RADIATION DOSE INHIBITS SPROUTING OF PRODUCTS SUCH AS POTATOES, ONION, GARLIC,
CHESTNUTS AND GINGER.
• IT HELPS IN DELAYING THE RIPENING OF SOME TROPICAL FRUITS LIKE BANANAS, AVOCADOS,
MANGOES.
3) DECONTAMINATION
4) PRODUCT QUALITY IMPROVEMENT

7. ADVANTAGES OF IRRADIATION
• MINIMIZE FOOD LOSSES (PREVENTS SPOILAGE OF FOOD, DELAY RIPENING AND PREVENTS
INFESTATION)
• IMPROVE PUBLIC HEALTH (REDUCES PATHOGENIC MICROORGANISMS AND PARASITES IN
FOOD CAUSING DISEASES)
• INCREASE INTERNATIONAL TRADE (PREVENTS INFESTATIONS AND INCREASES SHELF LIFE
USEFUL FOR LONG DISTANCE TRADE)
• AN ALTERNATIVE TO FUMIGATION OF FOOD
• INCREASE ENERGY SAVING

8. REDUCTION OF PATHOGENIC
MICROORGANISMS
• IRRADIATION IS CURRENTLY THE ONLY KNOWN METHOD TO INACTIVATE PATHOGENS LIKE E.COLI,
SALMONELLA, VIBRIO, ETC., IN RAW AND FROZEN FOODS.
• PATHOGENS ARE SENSITIVE TO LOW LEVELS OF IONISING RADIATION.
• AS THE IRRADIATION DOSE INCREASES, MORE MICROORGANISMS ARE AFFECTED BUT A HIGHER DOSE
INTRODUCE CHANGES IN SENSORY QUALITIES AND A BALANCE MUST BE ATTAINED BETWEEN THE
OPTIMUM DOSE REQUIRED.
• EGGS AND EGG PRODUCTS ARE OFTEN CONTAMINATED WITH SALMONELLA.
• FROZEN AND DRIED EGG COULD BE IRRADIATED WITHOUT QUALITY LOSS AND THE OPTIMUM DOE
PROVIDED WILL HAVE SUFFICIENT HYGIENIC PROTECTION.

9. EFFECTS ON MICROORGANISMS AND FOOD
COMPONENTS
• AFFECTS MICROORGANISMS LIKE BACTERIA, YEASTS AND MOULDS.
• CAUSES LESIONS IN GENETIC MATERIAL OF THE CELLS, EFFECTIVELY PREVENTING IT FROM
CARRYING OUT BIOLOGICAL PROCESSES NECESSARY FOR IT CONTINUED EXISTENCE.
• THE PRINCIPLE TARGETS OF FOOD IRRADIATION ARE NUCLEIC ACIDS (WHICH PREVENTS
REPLICATION AND CELL REPRODUCTION) AND MEMBRANE LIPIDS (FUNCTIONS AS
PERMEABILITY AND HAS MEMBRANE ENZYMES).

10. SUSCEPTIBILITY OF MICROORGANISMS TO
IRRADIATION

11. NUTRITIONAL QUALITY OF IRRADIATED
FOODS
• AS IRRADIATION IS A COLD PROCESS, IT DOES NOT SUBSTANTIALLY RAISE THE
TEMPERATURE OF THE FOOD BEING PROCESSED.
• NUTRIENT LOSSES ARE SMALL AND SIGNIFICANTLY LESS THAN LOSSES ASSOCIATED WITH
OTHER METHODS OF PRESERVATION SUCH AS CANNING, DRYING , HEAT PASTEURIZATION.
• IT IMPROVES PRODUCT RECOVERY AND HIGHER JUICE YIELD IN FRUITS.
• IRRADIATION DOES NOT LEAVE ANY CHEMICAL RESIDUES IN FOODS.
• INCREASES SHELF LIFE OF THE PRODUCTS AND ALSO MICROBIOLOGICAL PROPERTIES.

12. FOOD IRRADIATION - SAFTEY
1) RADIOLOGIC AND TOXICOLOGIC SAFETY-
• NEITHER THE FOOD NOR THE PACKAGING BECOMES RADIOACTIVE.
• NO CONCERN FOR UNIQUE RADIOLYTIC PRODUCTS.
• ANIMAL FEEDING STUDIES SINCE 1950 WITH METABOLIC, REPRODUCTIVE AND MUTAGENIC
ENDPOINTS SHOWS THAT FOOD IRRADIATION IS SAFE UNDER SPECIFIED CONDITIONS.
2) NUTRITIONAL ADEQUACY –
• CHANGES SIMILAR TO THOSE LIKE CANNING, PASTEURIZATION, COOKING, HEAT PROCESSING.
• PROTEINS ARE RELATIVELY IRRADIATION RESISTANT.
• FATS CAN BE OXIDIZED (RANCIDITY, ODOUR CHANGES).

13. 3) MICROBIOLOGIC SAFETY –
• VIRUSES , SPORES AND PRIONS ARE RESISTANT TO RADIATION.
• GRAM NEGATIVE SPOILAGE BACTERIA MORE SUSCEPTIBLE THAN PATHOGENIC BACTERIA.
• CLOSTRIDIUM BOTULINUM IS IRRADIATION RESISTANT.
• INCREASE IN MYCOTOXIN AFTER IRRADIATION.

14. PROBLEMS IN IRRADIATION OF FOODS IN
PLASTIC CONTAINERS
• PRODUCTION OF GAS AND VOLATILE COMPOUNDS WHICH MAY MIGRATE INTO THE FOOD AND CAUSE OFF-
FLAVOURS.
• AT STERILIZING DOSES, NYLON GIVES RISE TO LITTLE OFF-ODOUR PRODUCTION.
• IN CASE OF POLYETHYLENE, SHORT FRAGMENTATIONS OF THE POLYMER ARE PRODUCED WHICH ENTER
THE FOOD.
• VOLATILE COMPOUNDS ARE FORMED IN POLYETHYLENE AND ORIENTED POLYPROPYLENE AFTER
IRRADIATION.
• 22 COMPOUNDS (POLYESTER TEREPHTHALATE), 40 COMPOUNDS (ORIENTED POLYPROPYLENE), AND ONLY
ACETONE WAS IDENTIFIED WAS IDENTIFIED FOR POLYETHYLENE, WHICH CAN BE A GOOD CANDIDATE FOR
IRRADIATION OF PACKAGED FOOD PRODUCTS.
• THESE COMPOUNDS ARE HYDROCARBONS, KETONES AND AROMATIC COMPOUNDS.

15. THANKYOU