This document provides an overview of food irradiation, including its sources, types, benefits, and demerits. Food irradiation involves exposing food to ionizing radiation like gamma rays, x-rays, or electron beams to kill harmful bacteria and pathogens. It extends shelf life by inhibiting spoilage and can be used to sterilize food. While it reduces foodborne illness risks, higher costs and potential effects on sensory qualities and nutrients are concerns. Proper labeling and use of the lowest effective dose aims to address safety issues with the process.

1. WELCOME

2. FOOD IRRADIATION
By : Sachin S. bhuva (Jr. M. Tech., PFE)

3. 1. INTRODUCTION
2. FOOD IRRADIATION
3. SOURCES OF IRRADIATION
4. TYPES OF IRRADIATION
5. BENEFITS
6. DEMERITS
7. LABELLING OF IRRADIATED FOODS
8. FUTURE ASPECTS OF IRRADIATION
9. REFERENCES
CONTENT

4. • Radiation : Process in which energy is emitted as particles or waves.
• Called ionising radiation when it is at a sufficiently high frequency.
• High enough to change atoms to an ion, but not to split atoms and
cause to become radioactive.
• Irradiation: The process of applying ionizing radiation to an object.
INTRODUCTION

5. • Deliberate treatment or exposure of food to ionizing
radiations from a radioactive or machine generated source,
under controlled conditions, to disinfect, sterilize and preserve
the food.
• Cold Pasteurization - kills harmful bacteria without heat.
• Unit - “Gray“ (Gy = joule/ kg of materials).
FOOD IRRADIATION

6. 1. Gamma Rays :
 Emitted from radioactive element (cobalt 60 / cesium 137).
 Excellent penetration power.
2. X-rays :
 Produced by reflecting a high energy stream of electrons into
food.
 High penetration power
 Efficiency of conversion from electrons to X rays is less than
10%.
 X-ray machines having a maximum energy of 5 MeV.
SOURCES OF IRRADIATION

7. 3. Electron beam :
 Stream of high-energy electrons propelled from an electron
accelerator into food.
 Can not penetrate very far.
 Used only for treatment of thin packages of food and free
flowing or falling grains.
 Accelerated electron machines having a maximum energy of 10
MeV.
SOURCES OF IRRADIATION

8. 1. Radappertization:
 Not recommended for most foods as high dose (approx. 30 kGy).
 Equivalent to radiation sterilization.
2. Radurization:
 Medium dose (1-10 kGy)
 Enhances keeping quality by reduction of spoilage caused by micro-
organisms.
 Referred as radiation pasteurization.
IRRADIATION TYPES

9. 3. Radicidation:
 Low dose (<1.0 kGy) - equivalent to pasteurization of milk.
4. Thermo-radiation:
 Combination of heat and radiation.
IRRADIATION TYPES
Dosimeter : Device to measure the amount of absorbed dose of
ionizing radiation in a food.

10. TABLE : IRRADIATION LEVEL FOR USE IN FOOD INDUSTRY
DOSE Purpose Examples
Radurization
(<1 kGy)
• Inhibit vegetable
sprouting
• Kill insects and larva
• Slow ripening
• Reduce parasites
• Eliminate spoilage
causing
microorganisms
Potatoes, Wheat,
Bananas, Pork
Radicidation
(1-10 kGy)
• Eliminate pathogenic
bacteria
• Kills Pathogens
Chicken, ground
beef, fruit and
vegetables
Radappertization
(>10 kGy)
• Commercially sterilizes
food
Sterilizes hospital
diets, Space mission
foods

11. BENEFITS

12. • Generate short-lived and transient radicals (e.g. the hydroxyl
radical, the hydrogen atom and solvated electrons).
• That in turn damages the bonds in the DNA molecules,
causing disruption in the genetic makeup of microbes
beyond its ability to repair.
• The target organism ceases all the processes of maturation
and reproduction.
1. PATHOGEN REDUCTION

13. • Low doses of radiation (up to 1 kGy) can prolong the shelf-
life of many fruits and vegetables.
• For example: Irradiating strawberries extends their
refrigerated shelf-life to up to three weeks without decay or
shrinkage, versus three to five days for untreated berries.
• Moreover irradiation also causes delay in sprouting and
ripening adding to shelf-life.
2. SHELF LIFE EXTENSION

14. • Irradiation of spices, herbs, and dry vegetable seasonings.
• It is an alternative to the use of chemicals or fumigants,
such as ethylene oxide and methyl bromide.
• Moreover unlike chemicals, irradiation does not leave any
residuals that can lead to reinfestation.
3. INSECT DISINFESTATION

15. • Irradiation can also be used to sterilize food, which can
then be stored for years without refrigeration.
• Sterilized food are used in hospitals for patients with
severely impaired immune systems, such as patients with
AIDS or undergoing chemotherapy.
4. STERLIZATION

16. • Unlike canning , to preserve foods requires no additional
liquid, nor does it cause the loss of natural juices.
• Destruction of microbes or any other living cells in food
makes it spoilage and decomposition free.
5. PRESERVATION

17. • Treating raw meat and poultry at slaughter plant with high
doses of irradiation can cause elimination of E. coli,
Salmonella, and Campylobacter.
• Irradiation of animal feeds could also prevent the spread of
Salmonella and other pathogens to livestock through feeds.
 IRRADIATION OF MEAT &
POULTRY

18. DEMERITS
Higher cost
Consumer perception
Effect on sensory quality
Effect on nutrients

19. • High capital cost.
• Requires a critical capacity and product volume for
economic operation.
1. Higher cost
• The main worries of conservative consumer organizations
includes safety, nutrition, detection, and labelling of
irradiated product.
2. Consumer perception

20. • Depends principally on the type of food and dose.
• Milk and certain other dairy products - most radiation
sensitive foods. Doses as low as 0.1 kGy will impart an off-
flavour to milk that most consumers find unacceptable.
• Some fresh fruits and vegetables may cause softening
because of the breakdown of cell walls.
• Colour is another property of meat that can be changed by
irradiation. Doses higher than 1.5 kGy may cause a brown
discoloration of meat exposed to air.
3. Effect on sensory quality

21. • Depends on the dose, food matrix and preparation method.
• Food molecules are made of water, lipids, proteins,
carbohydrates and vitamins.
• Radiation energy generates a degradative reaction when it
interacts with food → “Radiolysis” that gives radiolytic
products.
4. Effect on nutrients

22. • Radiolysis of water molecules produce hydroxyl radicals.
• Highly reactive species that can cause characteristics
associated with food spoilage e.g.: off-flavour & off-odours.
• To minimize this effects:
 Apply lowest effective irradiation dose.
 Irradiate at lower temperature.
 Choose appropriate packaging in terms of moisture and
oxygen barrier properties.
 Food Water

23. • Absence of oxygen leads to cleavage of interatomic bonds -
producing compounds e.g. CO2, alkanes, alkenes and
aldehydes.
• Presence of oxygen, lipids are highly vulnerable to oxidation
by free radicals - yields peroxide, carbonyl compounds &
alcohols - Rancidity.
• To minimize this effects:
 Vacuum packaged & low temperature during irradiation.
 Adding lipid-soluble antioxidants.
 Use lowest irradiation dose.
 Food Lipids

24. • Proteins are not significantly degraded at low doses of
irradiation.
• Does not inactivate enzymes involved in food
deterioration.
• Most enzymes survives higher doses.
• Biological value of protein remain high.
• Availability of essential amino acids is not compromised.
 Food Proteins

25. • Large CHO molecules (polysaccharides) are broken down.
• Depolymerisation reduces gelling and functional properties
such as starches and gums.
• Effect on simple sugar is negligible.
 Food Carbohydrates
• Have varying degrees on sensitivity
• Some shows sensitivity at higher dose, e.g.: Vitamin A, C,
E and B1
• Sensitivity is apparent in food packaged under air.
 Food Vitamins

26. • United States currently has the most
widespread approvals for the use of
irradiation for food.
• FDA has required labelling of irradiated
food products since 1966.
• Radura logo required since 1986.
• International symbol indicating product
treated with irradiation.
• Usually green and resembles a plant in
circle. The top half of the circle is dashed.
LABELLING OF IRRADIATED FOODS

27.  Reddy SM (2015), 1st ed. Basic Food Science and Technology, New Age
International Publishers, New Delhi, 158-165.
 Manay NS and Shadaksharaswamy M (2008), 3rd ed. Food Facts and Principles,
New Age International P Ltd. New Delhi, 442-445.
 Khader V (2016), Textbook of Food Science and Technology, Directorate of
Knowledge, Management in Agriculture, ICAR, New Delhi, 418-425.
 Potter NN and Hotchkins JH (2007), 5th ed. Food Science, CBS Publishers &
Distributors, New Delhi, 245-256.
 http://nptel.ac.in/courses/103107088/module19/lecture1/lecture1.pdf
REFERENCES

28. Thank you…