Preservation of foods by irradiation method

1. BY,
DEEPIKA.S
M.Tech BIOTECHNOLOGY

2. Food preservation is the technique used to prevent food spoilage, food poisoning, and
microbial contamination in food.
Food preservation is the procedure by which food is treated and handled to stop or slow
down food spoilage, loss of quality, edibility or nutritional value and thus allow for longer
food storage.
Food preservation is known "as the science which deals with the process of prevention of
decay or spoilage of food thus allowing it to be stored in a fit condition for future use".
INTRODUCTION

3. 1. Asepsis, or keeping out microorganisms.
2. Removal of microorganisms.
3. Maintenance of anaerobic conditions.
4. Use of high temperatures.
5. Use of low temperatures.
6. Drying.
7. Use of chemical preservatives, either developed
by microorganisms or added.
8. Irradiation.
9. Mechanical destruction of microorganisms, e.g.,
by grinding, high pressures
PRINCIPLES OF FOOD PRESERVATION

4. METHODS OF FOOD PRESERVATION

5.  Food irradiation is the process of exposing food to a carefully controlled amount of
energy in the form of high-speed particles or rays.
 Food irradiation, being a cold process, can be used to inactivate spoilage and disease-
causing bacteria in solid foods such as meat, poultry, seafood, and spices,also kill insect
eggs and larvae in fresh fruits and vegetables without changing the foods’ quality.
 Its ability to inactivate pathogenic bacteria in frozen food is unique.
 The process of food irradiation is called “cold pasteurization” because it kills harmful
bacteria without the use of heat.
 Since irradiation is a cold pasteurization process, foods remain in the same physical state
after irradiation as before.
FOOD IRRADIATION

6. INONISING AND NON IONISING RADIATIONS

7. HOW IS FOOD IRRADIATED?

12.  The Food and Drug Administration (FDA) is responsible for regulating the sources of
radiation that are used to irradiate food.
 FDA approves a source of radiation for use on foods only after it has determined that
irradiating the food is safe.
 FDA has evaluated the safety of irradiated food for more than thirty years and has
found the process to be safe.
 The World Health Organization (WHO), the Centers for Disease Control and
Prevention (CDC) and the U.S. Department of Agriculture (USDA) have also
endorsed the safety of irradiated food.
IS IRRADIATED FOOD SAFE TO EAT?
FDA

13. FDA has approved a variety of foods for irradiation including:
 Beef and Pork
 Crustaceans (e.g., lobster, shrimp, and crab)
 Fresh Fruits and Vegetables
 Lettuce and Spinach
 Molluscan Shellfish (e.g., oysters, clams, mussels, and scallops)
 Poultry
 Seeds for Sprouting (e.g., for alfalfa sprouts)
 Shell Eggs
 Spices and Seasonings
WHICH FOODS HAVE BEEN APPROVED FOR IRRADIATION?

14. FDA requires that irradiated foods bear the international symbol for irradiation. Look for
the Radura symbol along with the statement “Treated with radiation” or “Treated by
irradiation” on the food label. Bulk foods, such as fruits and vegetables, are required to
be individually labeled or to have a label next to the sale container. FDA does not require
that individual ingredients in multiingredient foods (e.g., spices) be labeled.
HOW WILL YOU KNOW IF THE FOOD HAS BEEN IRRADIATED?

15.  By disrupting the biological processes that lead to decay.
 In their interaction with water and other molecules that make upfood and living
organisms, radiation energy is absorbed by the molecules they contact.
 The reactions with the DNA cause the death of microorganisms and insects and
impair the ability
HOW IRRADIATION WORKS?

16. Dose and dose rate
 Ionizing energy processes create enough of an absorbed dose to destroy microbes.The
international unit for measurement of radiation is the Gray (Gy).
 One Gray represents one joule of energy absorbed per kilogram of irradiated product. One
Gy is equivalent to 100 rad (radiation absorbed dose).
 Depending upon the mass and thickness of the food the desired dose is achieved by the
time of exposure and by the location of the product relative to the source.
 Unit of absorbed dose in food is kGy (kilograys).
DOSE

17. Levels of food irradiation
• Radurization (low) < 1 kGy
• Radicidation (medium) 1-10 kGy
• Rappertization (high) > 10kGy

18. IRRADIATION MULTIPLE USES

22. APPLICATIONS

23. IRRADIATION UNIT

24. IRRADIATION FACILITIES

25. Foods such as fresh meat and
spices leave processing facilities
and arrive at facilities that use
radiation to kill germs that can
make you sick
At the irradiation facility, foods
ride on a conveyor belt through an
irradiation chamber.
PROCESS FLOW
① ②

26. In the chamber, foods pass
under a beam of radiation.
This kills germs by breaking the
bonds that hold the germ's DNA
together.
Once the food leaves the irradiation
chamber, most of the germs are
destroyed.
3 4

27. The irradiated food goes to
grocery stores and food
service facilities.
You can Identify irradiated products by
looking for the Radura symbol, shown
here. It will be on the food label or the
product sign with "Treated with radiation"
5 6

28. PATHOGEN REDUCTION
 Generate short-lived and transient radicals.
 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.
SHELF LIFE EXTENSION
 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 also causes delay in sprouting
and ripening adding to shelf-life.
ADAVNTAGES

29. INSECT DISINFESTATION
 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.
STERLIZATION
 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.

30. Effects on microorganisms
Bactericidal efficiency of a given dose of
irradiation depends on following factors
• Kind and species of organism
• Number of organisms originally present.
• Presence or absence of oxygen.
• Physical state of the food
• Condition of organism.
• Composition of food.
EFFECTS

31. Effects on foods.
In meat
• pH of meat rises.
• Destruction of glutathione.
• Increase in carbonyl compounds, hydrogen sulphide & methyl mercaptan.
In fats and lipids
• Destruction of natural antioxidants and oxidation followed by partial polymerization.
• Increase in carbonyl compounds.
In vitamins
• Generally B-complex vitamins levels are reduced in food.
In enzymes.
• Some of the food enzymes are reduces.

32. DISADVANTAGES
Irradiated foods may
form chemical
products called
"radiolytic products"
Some foods such as dairy products and
eggs cannot be irradiated because it
causes changes in flavour and texture
of food. It can causes undesirable
flavor and texture changes.

33. Food irradiation
can destroy
bacterial spores
but is not effective
against viruses
Reduces the nutritional
content of food and
unknown long term
effects on human
health.
Increased consumer
cost- approximately 3
to 5 cents more a
pound than non-
irradiated meats

34. IN INDIAN MARKET

35. CASE STUDIES

39. Food irradiation can help
decrease the recent increases in
food-borne illnesses regardless
of the prices, and possible side
effects.
CONCLUSION