Food irradiation

1. IRRADIATION
TANYA SHARMA
M.Sc. Food Technology
Roll no. 22412FST023
FOOD PROCESSING

2. Content
INTRODUCTION
WHY IRRADIATED
FOODS? DOSES RATE
ADVANTAGES AND
LIMITATIONS
REGULATION OF
IRRADIATED FOODS
CONCLUSION

3. INTRODUCTION
• Irradiation is the process of applying low levels of
radiation to any food material to sterilize or extend
its shelf life.
• It is a physical method that involves exposing the
prepackaged or bulk foodstuffs to gamma rays, x-
rays, or electrons.
• Food is generally irradiated with gamma radiation
from a radioisotope source, or with electrons or x-
rays generated using an electron accelerator.
These rays have high penetration power and thus
can treat foods for the purpose of preservation and
quality improvement.
• During exposure of food the amount of ionizing
radiation absorbed is termed ‘radiation absorbed
dose’ [rad] and is measured in units of rads or
Grays.
• Irradiation has the potential to enhance food safety
for fresh foods that will be consumed raw and for
raw foods that require further processing.
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4. CONTINUE…
• Food irradiation mainly is done by the radioactive element cobalt-60 as the source of
high energy gamma rays. Gamma rays are electromagnetic waves or photons emitted
from the nucleus of an atom.
• These gamma rays have energy to dislodge electrons from food molecules, and to
convert them into ions which are electrically charged.
• The radiation dose varies depending on the thickness moisture, and characteristics of
the foods. External factors, such as temperature, the presence or absence of oxygen,
and subsequent storage conditions, also influence the effectiveness of radiation.
• In general, irradiation of food does not significantly affect the protein, lipid, and
carbohydrate quality. Minerals are stable to food irradiation. The overall chemical
changes in food due to irradiation are relatively minor and hence there is little change in
the nutritional quality.

5. Why Irradiated Food?
1. Prevention of foodborne illness
• Effectively eliminates microbes; Salmonella and E.coli
2. Preservation
• destroy/ inactivate organisms that cause spoilage and
decomposition
3. Control of insects
• Destroys insects e.g.: imported fruits.
4. Sterilization
• Useful for patients in the hospital especially with impaired
immunity.
5. Delays of sprouting and ripening
• Lengthen the longevity of products e.g. potatoes.
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6. 6
• Ionizing energy processes create enough of an absorbed dose to
destroy microbes
• Unit of absorbed dose in food is kGy (kilograys)
• Dose can be divided into three categories:
1. Radicidation
2. Radurization
3. Raddappertization
Dose and dose rate

7. 7
Radicidation ( “low” doses<1 kGy )
• Control insects in grains and fruit
• Inhibit sprouting in tuber
• Delay the ripening of some fruits/vegetables
• Reduce the problems of parasites in products of animal origin.
(e.g.: Trichinella spiralis in pork )
DOSE AND DOSE RATE

8. 8
Radurization (“Medium” dose 1~10kGy)
• Control Salmonella, Shigella, Campylobacter, Yersinia, Listeria and
E.coli in meat poultry and fish
• Delay mold growth on strawberries and other fruits
Radappertization (“High” dose >than 10kGy)
• Kill microorganisms and insects in spices
• Commercially sterilize foods, destroying all microorganisms of
public health concern(I.e., special diets for people with weakened
immune systems).
DOSE AND DOSE RATE

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• To make the food become radioactive, it will
require a lot of energy;15MeV.
• Foods are actually naturally radioactive
• Due to natural presence of Ca, P, K, and S
elements in the food
• The longer the storage time of irradiated food,
more natural radioisotopes have time to
undergo decay.
DOES THE FOOD BECOME RADIOACTIVE?

10. 10
Foods have been approved for
irradiation
FDA has approved a variety of foods for irradiation in USA
including:
• Beef and pork
• Poultry
• Mollusk shellfish
• Shell eggs
• Fresh fruits and vegetables
• Lettuce and spinach
• Spices and seasonings
• Seeds for sprouting

11. Food items approved for radiation preservation under
PFA Rules, 1955 and FSSA regulations, 2011
•
• Name of food Purpose Dose (kGy)
• Minimum Maximum
• Onion Sprout inhibition 0.03 0.09
• Potato0.06 0.15
• Ginger, garlic and shallots (Small onion) 0.03 0.15
• Mango Disinfestation 0.25 0.75
• Rice 0.25 1.00
• Semolina (sooji, rawa), wheat atta and maida 0.25 1.0
• Raisin, figs and dried dates 0.25 0.75
• Meat and meat products including chicken Shelf-life extension and pathogen
control 2.5 4
• Spices Microbial decontamination 6 14
• Fresh sea foods Shelf-life extension and pathogen control 1.0
3.0
• Frozen sea foods 4.0 6.0
• Dried sea foods Disinfestation 0.25 1.0
• Pulses

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Irradiated Food Products

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Advantages of Food Irradiation
• Radiation processing does not change texture and freshness of food, unlike heat. In fact,
it is difficult to distinguish between irradiated and non-irradiated food on the basis of color,
flavor, taste, aroma or appearance.
• Radiation processing does not affect significantly nutritional value, flavor, texture and
appearance of food.
• Radiation cannot induce any radioactivity in food and does not leave any harmful or toxic
radioactive residues on foods.
• It is a very effective method due to its highly penetrating nature of the radiation energy
and can be used on packed food commodities.
• Prepackaged foods can be made sterile thus improving shelf-life.

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Limitation of Food Irradiation
• Radiation processing cannot be applied to all kinds of foods.
• It cannot destroy already present pesticides and toxins in foods.
• Compliance of a particular food commodity to radiation processing has to
be tested first in a laboratory.
• Only those foods for which specific benefits are achieved by applying
appropriate doses and those duly permitted under the PFA Rules, (1955)
and now FSSA regulations (2011) can be processed by radiation.

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Regulation of Irradiated Food
o Considered as a food additives by the FDA
o For approval for any irradiated food, FDA requires the
foods labelled with statement:
1. Treated by ionizing energy/treated by irradiation
2. International symbol of irradiation, Radura
o Labelling requirements apply only to foods sold in
stores
o No labelling requirements if minor ingredients in other
foods and restaurant foods.

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Conclusion
• Consumer are gaining knowledge about the
benefits of food irradiation and it’s potential to
reduce the risk of foodborne disease but the
process is not a replacement for proper food
handling practices.
• Irradiation like other prevention methods,
however measures have to be taken to prevent
food borne illness