Irradiation is a process that exposes food to gamma rays, x-rays or electrons to kill microorganisms and insects, improving shelf life and safety without generating heat. Key radiations used are ultraviolet, beta rays, gamma rays and x-rays. Irradiation breaks chemical bonds in pathogens but can partially degrade some vitamins and nutrients. Extensive research has found irradiated food to be safe for human consumption. Common foods approved for irradiation include beef, pork, poultry, shellfish, eggs and various fruits and vegetables.

1. PRESERVATION OF FOOD BY
IRRADIATION
PRESENTED BY
ENA ATHAIDE
MSc- 1 BIOCHEMISTRY
INSTITUTE OF SCIENCE

3. Food Preservation
Meaning
Need
Causes of food spoilage

4. WHAT IS IRRADIATION
PROCESSING
Exposing food to gamma rays,
x-rays or electrons to improve
shelf life and safety.
Irradiation breaks chemical
bonds killing microorganisms,
insects.
Key advantage: no heat
generated

5. RADIATIONS USED IN
PRESERVATION
Ultraviolet(UV light)
Beta Rays
Gamma Rays
X- Rays
Microwaves

6. Application of Radiation
Most widely used techniques
of irradiating food are gamma
radiation from CO60 and Cs
137
Electron beams from linear
accelerators

10. RADIATION TREATMENT
OF FOOD
Radappertization : used in
canning industry , 30-40 kGy.
Radicidation:equivalent to
pasteurization of milk,2.5-10kGy.
Radurization:equivalent to
pasteurization,0.75-2.5kGy.

11. * kGy (kilogray) One Gy is equivalent to energy of 1 joule absorbed by one
kilogram of food; 1000 Gy = 1 kilogray kGy. 0.005 kGy dose is sufficient
to kill humans. (Another unit of absorbed radiation dose is the rad.
One Gy = 100 rad.)

14. Effects on Food Quality
 NUTRITIONAL EFFECTS
Proteins: aromatic amino acids
affected.
Lipids: production of carbonyls ,
organoleptic effect : rancidity.
Degradation of structural
polysaccharides : pectin and
cellulose.

15.  Partial destruction of
Vitamins:
Thiamine,niacin,biotin.
 MUTAGENICITY :
Example: may produce
disease resistant
microorganisms.

16. It does not inactivate dangerous toxins which
have already been produced by bacteria prior to
irradiation. In some cases, such as C. botulism, it
is the toxin produced by the bacteria, rather than
the bacteria itself, which poses the health
hazard.
 It does not prevent the aging of the fruit and
vegetables that can lower their nutritional value,
taste and flavors.
 Irradiation also unavoidably kills off bacteria
that produce the smells that warn you when food
is going "bad."

17. Extensive scientific research
reviewed by the World Health
Organization (WHO) and the U.S.
Food and Drug Administration has
indicated that irradiated food is
safe to eat (WHO, 1994; U.S.
Department of Health and Human
Services, 1997).

18. What Foods Have Been Approved for Irradiation?
FDA has approved a variety of foods for
irradiation in the United States including:
Beef and Pork
Poultry
Shellfish(e.g., oysters, clams, mussels, and
scallops)
Shell Eggs
Fresh Fruits and Vegetables
Lettuce and Spinach
Spices and Seasonings

19. Research
Effects of gamma radiation on the
biological, physico-chemical,
nutritional and antioxidant
parameters of chestnuts.
Control of Listeria monocytogenes
on frankfurters and cooked pork
chops by irradiation combined with
modified atmosphere packaging.

20. References
James M.Jay,1996, Modern food
microbiology, Wayne state
university,CBS publishers.pg-290-
307.
J.S.Smith,Pillai,Irradiation and
food safety, Food
Technol,Vol.58,no.11,pg-48-
55,Nov 2004.

21. Urbain,W.M,Food
irradiation,1986,Dep.of Food Science
and Human nutrition,Michigan state
university,London,Academic press
Inc.pg:118-123
Issues in Food safety,United States
dept of agriculture, economic
research service, agriculture
information, Bulletin No.757/Aug 2000

22.  Antonio AL, Carocho M, Bento A, Quintana B,
Luisa Botelho M, Ferreira IC,Effects of gamma
radiation on the biological, physico-chemical,
nutritional and antioxidant parameters of
chestnuts, Food Chem Toxicol. 2012
Sep;50(9):3234-42. Epub 2012 Jun
23.,pubmed.
 Kudra LL, Sebranek JG, Dickson JS, Larson
EM, Mendonca AF, Prusa KJ, Cordray JC,
Jackson-Davis A, Lu Z. Control of Listeria
monocytogenes on frankfurters and cooked
pork chops by irradiation combined with
modified atmosphere packaging. J Food Prot.
2012 Jun;75(6):1063-70.pubmed.

23. Radiation, Food and Water, Google Image
Result for
http://www.compafoodministry.org/wp-
content/uploads/2012/07/Food-2.jpg.
U.S Environmental Protection Agency,
Food Irradiation,
http://www.epa.gov/radtown/food-
irradiation.html
Electron accelerator
image:http://ccr.ucdavis.edu/irr/how_food_
irr.

24. FDA(Food and Drug Administration)
http://www.fda.gov/Food/ResourcesFor
You/Consumers/ucm261680.html.
http://www.fda.gov/Food/ResourcesFor
You/Consumers/ucm261680.html.