Gamma radiation can be used to enhance the shelf life of foods by disrupting biological processes that cause decay. It works by ionizing water and other food molecules, generating ions and radicals that can destroy microorganisms and inhibit spoilage. Common applications include reducing pathogens to increase safety, prolonging shelf life by limiting microbial growth, and controlling ripening/sprouting. While radiation processing maintains nutritional quality and fresh appearance, it has limitations in application and cannot make spoiled food safe. Over 40 countries commercially approve irradiation of foods like spices, grains, meat and produce.

1. Department of Food Science
Topic
ON
Application of gamma radiation technology for
enhancement of shelf life of food
Submited by;- Presented by:-
Dr .S.S. Shukla Kuldeep Sharma
Roll no. 6460
B.Sc. 4th year
COLLEGE OF AGRICULTURE
JAWAHARLAL NEHRU KRISHI VISHWA VIDYALAYA JABALPUR (M.P.)

2. In 1903 Rutherford demonstrated that, if the applied
magnetic field were strong enough, the alpha
radiation itself could also be deflected and behave as if
positively charged. At almost the same time , however
it was found that :
The portion of the alpha radiation was highly
penetrating and was undeflected in even the strongest
magnetic field. The component was termed as gamma
radiation.
Gamma Radiation

3.  Gamma rays are emitted by radioisotopes such as
Cobalt-60 and Caesium-137 while electrons and X-
rays are generated by machines using electricity.
 Radiation processing of food is one of the latest
methods developed for food preservation

4.  Alongside traditional methods of processing
and preserving food, the technology of food
irradiation is gaining more and more attention
around the world. In at least 39 countries,
their health and safety authorities have
approved irradiation of more than 40 different
foods. These approvals include spices, grains,
chicken, fruits, and vegetables. Twenty-nine
of these countries were using food irradiation
as a process for commercial purposes as of
1995.

5. Relative penetration power of alpha, beta
and gamma radiation

6. How irradiation works
 Irradiation works by disrupting the biological
processes that lead to decay. In their interaction with
water and other molecules, that make up food and
living organisms, radiation energy is absorbed by the
molecules they contact.

7.  The product of ionization may be electrically
charged (ions) or neutral (free radicals). These
then further react to cause change known as
radiolysis.
 The water is ionised by radiation. Electrons are
expelled from water molecules and break the
chemical bond. The products then recombines to
form hydrogen, Hydrogen peroxide, hydrogen
radical (H),hydroxyl radicals and hydroperoxyl
radicals(H2O )
 The radicles are short lived ( less than 10-5s) but
they are sufficient to destroy bacterial cell.

8. How do we irradiate food
 Radiation processing of food is carried out inside an
irradiation chamber shielded by 1.5 - 1.8 m thick
concrete walls. Food either pre-packed or in-bulk
placed in suitable containers is sent into the
irradiation chamber with the help of an automatic
conveyor.
 The conveyor goes through a concrete wall labyrinth,
which prevents radiation from reaching the work area
and operator room.
 When the facility is not in use the radiation source is
stored under 6 m deep water. The water shield does
not allow radiation to escape in to the irradiation
chamber, thus permitting free access to personnel to
carry out plant maintenance.

9. • For treating food, the source is brought to the
irradiation position above the water level after
activation of all safety devices.
• The goods in aluminium carriers or tote boxes are
mechanically positioned around the source rack and
are turned round their own axis, so that contents are
irradiated on both the sides.
• The absorbed dose is determined by the residence
time of the carrier or tote box in irradiation position.
• Absorbed dose is checked by placing dosimeters at
various positions in a tote box or carrier

10. Effect on microorganisms
 The reactive ions produced by irradiating foods,
injure or destroy micro-organism by changing the
structure of cell membrane and effecting
metabolic enzyme activity.
 More important effect on DNA and RNA
molecules in the cell nuclei.
 The sensitivity of micro organism to radiation is
expressed as the D10 value ( the dose of radiation
that reduces microbial population to 10% of its
initial value)
 Viruses are very resistant to irradiation and are
unlikely to be affected by the dose levels used in
commercial processing

11. Organism Approximate lethal dose (kGy)
Insects 0.22 to 0.93
Viruses 10 teo 40
Yeasts (fermentative) 4 to 9
Yeasts (film) 3.7 to 18
Molds (with spores 1.3 to 11
Bacteria (cells of pathogens):
Mycobacterium tuberculosis
Staphylococcus aureus
Cornybacterium diphtheriae
Salmonella spp.
1.4
1.4 to 7.0
4.2
3.7 to 4.8
Approximate Killing Doses of Ionizing Radiation for
micro organisms (kGy)

12. Effect on foods
 Induced radioactivity:
 At recommended doses Cobalt -60 and cesium 137
have insufficient emission energies to induce
radioactivity.
 Radiolytic products: Ions and radicles produced
during irradiation are capable of reacting with
component of food to produce radiolytic product
 Nutritional and Sensory value

13. Potential Applications of Gamma Radiation
Sterilisation ( or radappertisation)
It is possible to sterilize meat and other product, the
dose required exceed the current limit of 10 kGy. A dose
of 48 kGy is needed for 12 D reduction of Cl. butulinum.
High dose make the product organoleptically un
acceptable.

14. Reduction of pathogens (radicidation)
Food poisoning bacteria such as salmonella
typhimurium are less resistant to radiation than Cl.
Botulinum ,and doses of 3-10 kGy are sufficient for
destruction.
Prolonging shelf life (or radurisation)
Relatively low doses are needed to destroy yeast,
moulds and non-spore forming bacteria. This
process is used to increase shelf life by an overall
reduction of vegetative cells.

15. Control of ripening
fruits and vegetables can be irradiated to extend their shelf life about 2-
3 time when stored at 100C
The ripening and maturation of fruits are arrested by inhibition of
hormone production and interupting the biochemical process of cell
division.
Disinfestations
Grain and tropical fruits may be infested with insect and larvae, they
reduces export potential . A low dose below 1 kGy is effective for
disifestation
Inhibition of Sprouting:
The technology is effective in inhibiting sprouting of potatoes, A dose
of about 150 Gy has been recommended. Similar doses are also
effective in preventing sprouting of onian and garlic.

16.  Radiation processing is a cold process and therefore, unlike heat,
it can be used on agricultural commodities without changing
their fresh-like character
 Radiation processing dose not alter significantly nutritional
value, flavour, texture and appearance of food
 Radiation using Cobalt-60 cannot induce any radioactivity in
food and does not leave any harmful or toxic radioactive residues
on foods as is the case with chemical fumigants
 Due to the highly penetrating nature of the radiation energy, it is
a very effective method
 Prepackaged foods can be treated for hygienization and
improving shelf-life
 The radiation processing facilities are environment friendly and
are safe to workers and public around
THE BENEFITS AND LIMITATIONS OF RADIATION PROCESSING OF FOOD
BENEFITS

17. Limitations
•Radiation processing is a need based technology and cannot be
applied to all kinds of foods
•Radiation processing cannot make a bad or spoiled food look good
•It cannot destroy already present pesticides and toxins in foods
•Amenability of a particular food commodity to radiation processing
has to be tested in a laboratory
•Only those foods for which specific benefits are achieved by applying
appropriate doses, and those duly permitted under the Prevention of
Food Adulteration Act (PFA) Rules, 1955, can be processed by radiation.

18. Radiation processed food cannot be recognized by sight, smell,
taste or touch. Codex Alimentarius Commission has endorsed a
green irradiation logo.

19. RADIATION PROCESSED FOODS IN MARKET PLACE
Sr.No. Country Food Commodities
1 Argentina Spices, onion
2 Bangladesh Onion, dry fish, pulses
3 Belgium Spices, dehydrated vegetables, deep frozen foods
4 Brazil Spices
5 Canada Spices
6 Chile Dehydrated vegetables, onion, potato, seafood
7 China
Spices and vegetable seasonings, Chinese sausage, garlic, apple,
potato, onion, dehydrated vegetables, sauces, rice, tomatoes, beef
8 France
Spices, vegetable seasonings, herbs, poultry (frozen boneless chicken,
dried fruits, frozen frog legs, shrimp, cereals, strawberries, dry fruits)
9 Hungary Spices, herbs
10 Indonesia Spices, rice, dry fish, mungbean

20. 11 Israel Poultry
12 Japan Potato
13
Korea
Republic
Spices, garlic powder, dry - mushrooms, fish & meat
14 Netherlands Spices, frozen products, poultry, dehydrated vegetables, egg powder
15 Norway Spices
16 Poland Onion, potato
17 South Africa Spices, shelf-stable foods, fruits, potato, cereals
18 Thailand Spices, fermented pork sausages, enzymes, onion, rice
19 UK Spices
20 USA Spices, poultry, fruits, vegetables
21 Vietnam Onion
22 Yugoslavia Spices

21. Radiation processed food