Irradiation preservation of foods

1. Irradiation Preservation of Foods
By: Nooshin Noshirvani
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2. 2

3. 3
the level of food loss is high (more than 40% for
fruits & vegetables and higher for fish & meat)
According to the United Nations, more than 30
percent of the mortality rate world-wide is caused
by alimentary diseases
Some agricultural products are important
commodities in international trade. (infestation of
several species of insects and mites)
The presence of parasites, some microorganisms,
yeast and moulds are also the source of problems,
(toxin formation)

4. According to Statistic Canada,
• the number of food-borne illnesses is estimated to be more than:
630 000 cases/year for Salmonella,
100 000 cases/year for Staphylococcus aureus,
19 000 cases/year for Shigella,
16 000 cases/year for Campylobacter jejuni
13 000 cases/year for E. coli O157: H7.
2800 cases/year for Listeria monocytogenes,
4
Canada USA

5. Newest Method:
Irradiation
5
Oldest
Methods
Drying
Fermenting
Salting
Smoking
Newer
Methods
freezing
Canning
Refrigeration
Preservatives
Pesticides
applied to fresh, frozen or
cooked products.
physical safe
environmentally
clean
efficient technology

6. • physical treatment that consists of exposing foods either prepackaged
or in bulk to the direct action of electronic, electromagnetic rays
• When made to bombard against materials, they can knock off an
electron from an atom or molecule causing ionization.
• For this reason, these are often called ionizing irradiation.
• The X- and gamma-rays are very short wavelength radiations that
have very high associated energy levels.
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7. 7

8. • Gamma Rays
 come from the spontaneous disintegration of radionuclides.
 cobalt-60 (1.17 and 1.33 MeV) : produced from cobalt-59
 caesium- 137 (0.662 MeV) : a spent fuel from nuclear reactors
 Nuclear Waste
 Good penetration
• Electron Beams
Stream of high-energy electrons propelled from an electron gun (maximum
energy 10 MeV).
Similar to Beta Particles
No Waste, In-line equipment
• X-rays
▫ beam of accelerated electrons is directed at a thin plate of gold (or other
metal), producing a stream of X-rays exiting from the other side (5 Mev)
▫ No Waste, In-line equipment, Good Penetration
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10. Gamma Rays
• Cobalt-60 the choice for gamma radiation source
• produced by neutron bombardment in a nuclear reactor of the metal cobalt-
59, then doubly encapsulated in stainless steel pencils to prevent any leakage
during its use in an irradiator.
• Cobalt-60 has a half-life of 5.3 years,
• highly penetrating and can be used to treat full boxes of fresh or frozen food.
• over 80% of the cobalt-60 available in the world market is produced in
Canada.
• Other producers are the Russian, Republic of China, India and South Africa.
• Cesium 137 is the only other gamma-emitting radionuclide suitable for
industrial processing of materials.
• It can be obtained by reprocessing spent, or used, nuclear fuel elements and
has a half-life of 30 years.
• There is no supply of commercial quantities of cesium-137.
10

11. Electron Beams
• Since the associated energy levels of these rays are too low to be
practical value in preservation, they need to be accelerated (in
cyclotrons, linear accelerators etc.) to make them acquire the
required energy.
• Since electrons cannot penetrate very far into food, compared with
gamma radiation or X-rays, they can be used only for treatment of
thin packages of food and free flowing or falling grains.
11

12. • chemical events as a
result of energy
deposition on target
molecule
Direct
• radicals formed from
indirect the radiolysis of water
12

13. • The international unit of measurement 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)
• The desired dose is achieved by the time of exposure and by the
location of the product relative to the source.
• depend upon the mass, bulk density and thickness of the food
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irradiation pasteurization

18. • The maximum dose of 10 kGy recommended by the Codex
General Standard for Irradiated Foods is equivalent to the heat
energy required to increase the temperature of water by 2.4ºC.
• Irradiation is often referred to as a ‘’cold pasteurization’’ process
as it can accomplish the same objective as thermal pasteurization
of liquid foods,
• For example milk, without any substantial increase in product
temperature.
18

19. • 1895 W. K. Von Roentgen discovers X-rays.
• 1896 H. Becquerel discovers radioactivity.
• 1896 F. Minsch suggests using ionizing radiation to kill
microorganisms in food.
• 1903 M. Curie described 3 different types of radiation – alpha, beta and
gamma.
• 1904 S. C. Prescott publishes effects of ionizing radiation on bacteria.
• 1905 U.S. and British patents are issued for the proposed use of killing
bacteria in food with ionizing radiation.
• 1921 B. Schwartz, a researcher at USDA, publishes studies about the
lethal effect of X-rays on Trichinella spiralis in pork.
• 1950s conduct research on food irradiation.
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20. • 1943 Preservation of ground beef by exposure to X-rays
demonstrated to be feasible.
• 1950 U.S. Atomic Energy Commission begins program using
radioisotopes for food preservation.
• 1953 U.S. Army begins food irradiation program.
• 1958 U.S. Federal Food, Drug and Cosmetic Act is amended, legally
defining ionizing radiation as a food additive rather than a process.
• USSR approves irradiation for potatoes and grain.
• 1960 Canada approves irradiation for potatoes.
• 1963 FDA approves irradiation for insect disinfestation of wheat and
wheat powder.
• 1964 FDA approves irradiation to inhibit sprouting in potatoes.
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21. 21
• 1965 FDA approves irradiation to extend the shelf life of potatoes.
• 1968 FDA and USDA rescind approval for irradiation of bacon granted in
1963.
• 1976 Joint FAO/IAEA/WHO Expert Committee on the Wholesomeness
and Safety of Food Irradiation approves several irradiated foods and
recommends that food irradiation be classified as a physical process.
• 1980 Joint FAO/IAEA/WHO Expert Committee concludes that any food
irradiated up to a maximum overall average dose of 10kGy presents no
toxicological hazard and requires no further testing.
• 1983 FDA and Canada approve irradiation for insect disinfestation in
spices and dry vegetable seasoning (38 commodities).

22. • 1985 FDA approves irradiation to control Trichinella spiralis in
pork and to disinfest dry enzyme preparations.
• 1986 FDA approves irradiation to delay ripening (maturation) of
some fruits and vegetables, and to decontaminate dry or
dehydrated enzyme preparations.
• 1990 FDA approves irradiation to control pathogens such as
Salmonella in fresh and frozen poultry.
• 1997(FDA) and 1999 (USDA) Approval of irradiation to control
pathogens in fresh and frozen red meats (beef, lamb and pork).
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23. • Wheat flour – control of mold
• White potatoes – inhibit sprouting
• Pork – kill Trichinia parasites
• Fruit and Vegetables – insect control; increase shelf life
• Herbs and Spices - sterilization
• Poultry – bacterial pathogen reduction
• Meat – bacterial pathogen reduction
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24. • Irradiation is a “cold” process, and therefore…
▫ Little if any change in physical appearance
 No textural or color changes as with traditional heat
preservation
• Possible chemical changes
▫ Off-flavors
▫ Tissue softening
24

25. Disinfestation
Shelf Life Extension
Decontamination
Product Quality Improvement
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26. 26

27. • Commercial processing of irradiated potatoes has been carried out in
Japan since 1973.
• important postharvest treatments
• A low dose of 0.15–0.50 kGy can damage insects at various stages of
development that might be present
• Irradiation can damage insect’s sexual viability or its capability of
becoming an adult
• Radiation disinfestation can facilitate trade in fresh fruits, such as
citrus, mangoes, and papayas which often harbour insect pests of
quarantine importance (0.2-0.7 KGy)
• a combination treatment of low doses of gamma irradiation (0.35 kGy).
and heat would be advantageous to cause complete killing of insects in
dates
27

28. methyl bromide &
phosphine
irradiation
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29. 29

30. • A very low radiation dose of 0.15 kGy or less (0.02–0.15), inhibits
sprouting of products such as potatoes, yams, onions, garlic,
ginger, and chestnuts.
• Yang et al found that the treatment of garlic bulbs with 0.15 kGy
can inhibit sprouting and reduce weight losses during storage
• The irradiation affects the flavor compounds of garlic.
• delay the ripening and senescence of some tropical fruits such as
bananas, litchis, avocados, papayas, and mangoes at 0.12–0.75
kGy
30

31. • Delay Microbial development in fruits
• Extends the shelf life of perishable products such as beef, poultry,
and seafood by decontamination of spoilage microorganisms.
• The shelf-life of many fruits and vegetables, meat, poultry, fish
and seafood can be considerably prolonged by treatment with
combinations of low-dose irradiation and refrigeration that do not
alter flavour or texture.
• Pseudomonas spp., are relatively sensitive to irradiation. (dose of
2.5 kGy) applied to fresh poultry carcasses enough to eliminate
Salmonella, and will also kill many, but not all, spoilage bacteria.
• This will double meat shelf-life, provided it is kept below 5°C
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32. 32

33. 33
• known as ‘’trichina-safe’’
• 0.3 Kgy for trichina &
0.5 (Toxoplasma gondii)
Destroy parasites
pasteurize
• low dose
• 1.0–2.0 kGy
• higher dose
• 3.0–20 kGy
sterilization

34. • Irradiation is currently the only known method to inactivate these
pathogens in raw and frozen food.
• Escherichia coli O157:H7, Salmonella, Campylobacter jejuni,
Listeria monocytogenes, and Vibrio
• Salmonella and C. jejuni are usually associated with poultry( 2.5 kGy )
• E. coli O157:H7 has also been linked to meat and dairy products in the
United Kingdom, hamburger meat, apple juice and water in the USA,
and vegetables in Japan
• Listeria monocytogenes has been associated with dairy products,
processed meats and other foods having a relatively long shelf-life
under refrigeration.
• Vibrio sppconsumption of raw mollusks.
34

35. 35
• sensitivity of Pathogens to low levels of ionising radiation
• As the irradiation dose increases more microorganisms are affected
but a higher dose, introduce changes in sensory qualities and a
balance must be attained between the optimum dose required
• Eggs and egg products are often contaminated with Salmonella
• Frozen egg and dried egg could be irradiated at doses of up to 2- 5
kGy without quality loss and that this dose provided sufficient
hygienic protection.
• Seafood (shellfish & frozen shrimp) is often contaminated with
pathogenic organisms such as Salmonella, Vibrio
parahaemolyticus, and Shigella, Aeromonas hydrophila. dose of
about 3 kGy

36. • astronauts in the NASA space shuttle programme
• their superior quality,
• safety
• variety,
• Limited commercial-scale sterilization of various ready-to-eat
foods by high dose irradiation has been carried out in South Africa
during the past 10 years to serve military personnel and campers,
yachters and hikers.
36

37. 37
improving product recovery
and higher juice yield in fruits
irradiation does not leave any
chemical residues in foods
Increase shelf life and
microbiological properties

38. 38
Minimize Food Losses
Improve Public Health
Increase International Trade
An Alternative to Fumigation of Food
Increase Energy Saving

39. • Especially in the Third
World, irradiation has high
potential where in many
cases food is spoiled during
postharvest stage
39
Disinfestation
sprout
inhibition
delayed
ripening

40. • Reduction of:
40
pathogenic
microorganisms parasites

41. 41
(i) infestation by
insects
(ii) infection by
microorganisms
(iii) their limited
shelf life
restricts long-distance shipments.

42. 42
ethylene
dibromide
ethylene
oxide
methyl
bromide
toxic nature and environmental
impact effect

43. 43
Canning
20,180 kJ/kg
Refrigeration
17,760 kJ/kg
frozen
storage
46,600 kJ/kg
refrigerated &
irradiated
17,860 kJ/kg

44. 44
• affects microorganisms, such as bacteria, yeasts, and molds
• causing lesions in the genetic material of the cell, effectively
preventing it from carrying out the biological processes necessary
for its continued existence
• The principal targets of irradiation are nucleic acids and membrane
lipids

45. Mode of Action
nucleic acids
prevention of
replication
cell reproduction
impossible
membrane lipids
functions, such
as permeability
membrane
enzymes
45

46. Main factor of
susceptibility
atmosphere
Presence of
oxygen
temperature Dose level Medium
Absence of
oxygen
Type of
organism
Size
Cell wall (Gram
positive of
negative)
46
Number and
age of cells

47. • As a rule, the simpler the life form, the more resistant it is to the
effects of irradiation.
Parasites and insect pests
• have large amounts of DNA
47
Humans Molds Bacteria viruses

48. 48

49. NO ACUTE
EFFECTS
STERILIZATION OF MICROORGANISMS
LETHAL TO
INSECTS
SPROUTING
INHIBITED
LETHAL
TO
HUMANS
1 10 102 103 104 105 106 107
Dose
(rad)
49

50. 50
Proteins
Effects of
Irradiation
Carbohydr
ates
Enzymes
Vitamins Lipids

51. peptide linkages
• not attacked
sulfur linkages
• attacked
hydrogen bonds
• attacked
51
Low doses : may cause molecular uncoiling, coagulation, unfolding, and even molecular cleavage
and splitting of amino acids
At 10 kGy radiation, overall increase in total free amino acids was observed mainly due to the rise in
the levels of glycine, valine, methionine, lysine, isoleucine, leucine, tyrosine, and phenylalanine
affects the functional properties of proteins
Egg
loss of viscosity in the white
off-flavors in the yolk
Milk
off-flavors
increase in rennet coagulation time
reduced heat stability

52. • break high-molecular-weight carbohydrates into smaller units
• softening of fruits and vegetables through breakdown of cell wall
materials, such as pectin
• Sugars may be hydrolyzed or oxidized
• irradiation of wheat at 0.2–10 kGy increase in initial total reducing
sugars and generation of bread flavor and aroma
• Irradiation of pure carbohydrates produced degradation products,
which have mutagenic and cytotoxic effects.
• However, these undesirable effects were produced using very
high dose of irradiation
52

53. • initiates the normal process of autoxidation of fats which gives rise
to rancid off-flavors
• The formation of peroxides and volatile compounds, and the
development of rancidity and off-flavors
• This process can be slowed by the elimination of oxygen by
vacuum or modified atmosphere
• The peroxide formed can also affect certain labile vitamins, such
as vitamins E and K
• The lipids in cereals degraded only at high doses of irradiation and
no significant effects on iodine value, acidity, or color intensity of
wheat flour lipids were observed
53

54. • The extent of vitamin C, E, and K destruction depends on the
dosage used,
• thiamine is very labile to irradiation.
• The losses are low with low dose
• Ascorbic acid in solution is quite labile to irradiation but in fruits
and vegetables seems quite stable at low doses of treatment
• Vitamins (antioxidant activity), such as A, B12, C, E, K, and
thiamine, are degraded when irradiation is carried out in the
presence of oxygen
54

55. • Enzymes in foods must be inactivated prior to irradiation because
it is much more resistant to radiation than microorganisms
• complete inactivation of enzymes requires about 5–10 times the
dose required for the destruction of microorganisms
• The D values of enzyme can be 50 kGy and almost four D values
would be required for complete destruction
• irradiated foods will be unstable during storage due to their
susceptibility to enzymatic attack than nonirradiated foods
55

56. • Fruits and Vegetables (Berries, Mangoes, Carrots, Papaya,
Strawberries)
• Spices
• Cereals and Grains
• Animal Foods (Poultry, Mutton, Beef, Pork, Processed Meats,
Fish and Fish Products)
56

57.  promising technology to maintain the quality of fresh fruits and vegetables because
• it has the potential to control both spoilage and pathogenic microbes
• physical means for pasteurization without changing the fresh state
• at a pasteurization dose (2–5 kGy) could control post-harvest spoilage and diseases
• undesirable symptoms are
• tissue softening
 partial depolymerization of cell wall polysaccharides, mainly cellulose and pectins
 damage to cell membrane
• enzymatic browning
57
Fungal
diseases
pathological
breakdown
insect
infestation.
tissue
damage
this technology should be used
in combination with
other treatments.

58. • irradiation with heat strong inactivation effect (1% survival) was
obtained when irradiation plus heat (1.25 kGy 46°C, 5 min)
• Papaya: 48.9°C for 20 min in combination delayed ripening with
optimum dose of 0.75 kGy
• heating and irradiation had a stronger interaction than heating and
chilling
• The oxidation can be minimized by irradiating in an atmosphere with
reduced oxygen content,
• low-dose irradiation combined with modified atmosphere is
increasingly considered for control of microorganisms and delayed
ripening
• Couture and Willemot showed the synergistic action of irradiation
combined with high carbon dioxide for control of mold development on
strawberries. (7% oxygen and 20% carbon dioxide and 1 kGy)
58

59. 59
Strawberry 1.5–2kGy
(3 kGy) 14 days.
Papaya &
mango (0.25 -1
kGy)
Mushroom (2 -
3kGy) two-fold

60. • Not all fruits and vegetables are suitable for irradiation because
undesirable changes in colour or texture, or both, limit their
acceptability.
• different varieties of the same fruit or vegetable may respond
differently to irradiation.
• The time of harvest and the physiological state also affects the
response of fruits and vegetables to irradiation
• For delaying ripening in fruits it is important to irradiate them
before ripening starts.
60

61. Shelf-life of strawberries can be
extended by irradiation!!!
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62. 62

63. • Spices, herbs and vegetable seasonings are valued for their distinctive
flavours, colours and aromas.
• they are often heavily contaminated with microorganisms because of
the environmental and processing conditions under which they are
produced (open air drying procedures)
• Before use in food the microbial load should be reduced.
• Because heat treatment can cause significant loss of flavour and aroma,
a ‘’cold process’’, such as irradiation, is ideal.
• Until recently, most spices and herbs were fumigated, usually with
sterilizing gases such as ethylene oxide to destroy contaminating
microorganisms
• the use of ethylene oxide was prohibited by an European Union (EU)
directive in 1991 and has been banned in a number of other countries
because it is a carcinogen.
63

64. • increasingly important use of irradiation for decontamination of
spices
• A dose of 2.5 kGy reduced the fungal and bacterial load by 2 log
cycles, and 7.5 kGy eliminated the fungal population of ground or
whole pepper.
64
Clostridium Staphylococcus Bacillus Aspergillus Fusarium

65. • Irradiation of spices on a commercial scale is practised in over 20
countries and global production has increased significantly from
about 5,000 tonnes in 1990 to over 60,000 tonnes in 1997.
• In the USA alone over 30,000 tonnes of spices, herbs and dry
ingredients were irradiated in 1997 as compared to 4,500 tonnes in
1993.
65

66. • with low doses of irradiation to eliminate fungi, since some of
these organisms can produce mycotoxins
• 0.2–1.0 kGy are effective in controlling insect infestation in
cereals
• Increasing the dose to 5 kGy totally kills the spores of many fungi,
which survive lower doses
• loaf volume and baking quality deteriorated above 5 kGy
irradiation irrespective of the baking formula.
66

67. • The irradiation is effective in preventing or delaying the microbial
spoilage of fresh meats and poultry.
• Early studies indicated that irradiation at doses between 0.25 and
1kGy under aerobic conditions increased microbiological shelf
life, but accelerated rancidity
• In case of meats, doses up to 2.5 kGy control Salmonella,
Campylobacter, Listeria monocytogenes, Streptococcus faecalis,
Staphylococus aureus, and Escherichia coli in poultry and other
meats.
• The doses in excess of 2.5 kGy may change flavor, odor, and
color, but these changes can be minimized by irradiating at low
temperature or in absence of oxygen
67

68. 68
oxidation of pigment
to yield brown or gray
discolorations by o2
drip loss from the cut
surface of lean,
oxidation of meat
lipids that causes off-flavors
by atmospheric
irradiation coupled with vacuum packaging
has the potential to extend the shelf life

69. 69
• dose of 2.5–5kGy dose since this can extend shelf life at chill
temperatures from 6 to 14 days without insignificant organoleptic
quality change

70. 70

71. • The amount of nitrite required in cured meats possibly can be
reduced by irradiation, thus the chance of nitrosamine formation
can be lowered
• can be reduced from normal levels of 120–150 to 20–40 mg/kg
without loss of organoleptic quality
71

72. 72

73. • control of pathogenic organisms and the extension of shelf life of
fresh fish could be achieved with relatively low doses 2.5 kGy
• Clostridium botulinum (A, B, E, and F) present in fish and fish
products remained unaffected by the low doses of irradiation.
• Thus, precautions during storage under 3°C and oxygen
availability to the product need to be taken
73

74. 74

75. • As irradiation is a cold process does not substantially raise the
temperature of the food being processed,
• nutrient losses are small and often significantly less than losses
associated with other methods of preservation such as canning,
drying and heat pasteurization.
75

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77. 77

78. 78
• Production of gas and volatiles compounds, which may migrate into the food and cause
off-flavors.
• At sterilizing doses, nylon gives rise to little off-odor production,
• in case of polyethylene, short fragmentations of the polymer are produced, which enter
the food
• Volatile compounds are formed in polyethylene, polyester terephthalate, and oriented
polypropylene after irradiation dose from 5 to 50kGy.
• Twenty-two compounds (polyester terephthalate), 40 (oriented polypropylene), and
only acetone was identified for polyethylene, which could be a good candidate for
irradiation of packaged food products.
• These compounds are hydrocarbons, ketones, and aromatic compounds

79. 79
The properties of polyethylene terephthalate (PET) are well preserved
during irradiation
At doses of 60 kGy and higher, some damage may occur in tin-coated steel
and aluminum containers, but at the level of sterilizing doses there should not
be any affect
At doses less than 20kGy, physical changes in flexible containers are
negligible.
High doses above 30 kGy cause brittleness in cellophanes, saran, and
plioform, while 20 kGy or more can cause inconsequential physical changes
in mylar, polyethane, vinyl, and polyethylene plastic films
At strong doses of 50kGy, mechanical properties of polymers can be
improved by cross-linking

80. 80

81. • the irradiation room
• A system to transport the food into and out of the room
• concrete shielding (1.5 - 1.8 metres thick) surrounding the
irradiation room, which ensures that ionising radiation does not
escape to the outside of the room.
81

82. • In the case of a gamma irradiator, the radionuclide source continuously
emits radiation and when not being used to treat food must be stored in
a water pool (usually 6 metres in depth).
• Known as one of the best shields against radiation energy, water
absorbs the radiation energy and protects workers from exposure if they
must enter the room.
• In contrast to gamma irradiators, machines producing high-energy
electrons operate on electricity and can be switched off.
• The transport system : conveyor or a rail system
• In a gamma irradiator, the size of the containers in which the food is
moved through the irradiation chamber can vary and pallets up to 1 m3
may be used
• with machines, the bulk or thickness of a product which can be treated
is much less and hence there is a fundamental design difference
between the two types of irradiator.
82

83. 83

84. 84

85. 85

86. 86

87. 87

88. 88

89. 89

90. Vietna
m
Ukraine
Isreal
China
China
90

91. • In 1980, it concluded that the irradiation of any food commodity up to an
overall average dose of 10 kGy presents no toxicological hazard and requires
no further testing.
• in 1983, of a worldwide standard covering irradiated foods.
• The standard was adopted by the ,(FAO) and (WHO), more than 150
governments.
• The Codex General Standard for food irradiation was based on the findings of
a Joint Expert Committee on Food Irradiation (JECFI) convened by the FAO,
WHO, and the International Atomic Energy Agency (IAEA)
• As of August 1999, over 30 countries are irradiating food for commercial
purposes.
• Today, health and safety authorities in over 40 countries have approved
irradiation of over 60 different foods, ranging from spices to grains to
deboned chicken meat, to beef, to fruits and vegetables
91

92. • In September 1997 a Study Group was jointly convened by the
WHO, FAO and IAEA to evaluate the wholesomeness of food
irradiated with doses above 10 kGy.
• This Study Group concluded that there is no scientific basis for
limiting absorbed doses to the upper level of 10 kGy as currently
recommended by the Codex Alimentarius Commission.
• Food irradiation technology is safe to such a degree that as long as
the sensory qualities of food are retained and harmful
microorganisms are destroyed, the actual amount of ionizing
radiation applied is of secondary consideration.
92

93. Interest in the irradiation process is increasing because of:
• persistently high food losses from infestation, contamination,
spoilage;
• Prohibition on the use of a number of chemical fumigants for
insect and microbial control in food,
• Effective alternative to protect food against insect damage and as a
quarantine treatment of fresh produce.
93

94. 94

95. • a few hundred thousand tonnes of food products and ingredients
are irradiated worldwide.
• This amount is small in comparison to the total volumes of
processed foods and not many of these irradiated food products
enter international commerce.
• Adopting public understanding and acceptance of the process.
95

96. • Major Problems of Irradiation
• Legal Aspects and Safety Issues
• Consumers’ Attitude
96

97. • has a low operating cost
• requires low energy
But:
high capital costs
requires a critical minimum capacity
threshold doses above which organoleptic changes and off-flavor
development occur at low doses all microorganisms and their
toxins will not be eliminated.
Limitation in packaging material
97

98. 98
• A joint FAO/IAEA/WHO Expert Committee on Food Irradiation
(IJECFI) concluded that irradiation of food up to an overall
average dose of 10 kGy causes no toxicological hazards and
introduces no special nutritional or microbiological problems
• Irradiation of food and agricultural products is currently allowed in
about 40 countries and approximately 60 commercial irradiation
facilities are operating in the United States
• The most common irradiated food products for commercial use are
spices and dry vegetable seasonings
• recent ban on the use of ethylene oxide for food by European
Union could increase the quantity of spices and vegetables
seasonings processed by irradiation in the near future

99. 99

100. 100

101. 101

102. 102

103. 103
• consumer education
• in advanced countries consumers at large are still not
knowledgeable about food irradiation.
• accurate information about safety, benefits, and limitations of food
irradiation

104. 104

105. 105
• NO. Neither irradiation nor any other food treatment can reverse
the spoilage process and make bad food good
• While irradiation can reduce or eliminate spoilage bacteria or
pathogenic microorganisms which may be present in a spoiled
food, it cannot improve its sensory properties , the bad appearance,
taste or smell will remain

106. • all exposures of workers to radiation are prevented because the
radiation source is shielded.
106

107. • Over the past 30 years, there have been a few major accidents at
industrial irradiation facilities that caused injury or death to
workers because of accidental exposure to a lethal dose of
radiation.
• All of the accidents happened because safety systems had been
deliberately bypassed and proper control procedures had not been
followed.
• None of these accidents endangered public health and
environmental safety.
107

108. • NO.
108
• free radicals are also formed by other food treatments, such as toasting of bread,
frying, and freeze drying, and during normal oxidation processes in food.
• They are generally very reactive, unstable structures, that continuously react with
substances to form stable products.
• Free radicals disappear by reacting with each other in the presence of liquids,
such as saliva in the mouth.
• Consequently, their ingestion does not create any toxicological or other
• harmful effects.

109. • NO.
• Energies from these radiation sources are too low to induce
radioactivity in any material, including food.
• If the acquired energy is too high, induced radioactivity in foods
could occur upon irradiation
109

110. • NO.
• Irradiation does not make food radioactive. Everything in our
environment, including food, contains trace amounts of
radioactivity.
• This means that this trace amount (about 150 to 200
becquerels/kg) of natural radioactivity from elements such as
potassium is unavoidable in our daily diets.
110

111. 111

112. • سازمان انرژی اتمی ایران که مقدمات ایجاد آن از اوایل سال ۱۳۵۳ فراهم گردیده بود، با
ً
تصویب قانون
سازمان انرژی اتمی در تاریخ ۱۳۵۳ عملا
به صورت یک /۴/ ۱۶ » شخصیت « حقوقی رسمیت یافت .
• صنایع غذایی، دامپزشکی، و دامپروری
• در حوزه صنایع غذایی تبدیلی کشاورزی نیز برای استریل کردن محصولات )از بین بردن
میکروبها ویروسها ، باکتریها و قارچها (می توان از کاربردهای مختلف انرژی هسته ای بهره برد.
• تکنیک های هسته ای در حوزه دامپزشکی موارد مصرفی چون تشخیص و درمان بیما ری های
دامی، تولید مثل دام، تغذیه دام، اصلاح نژاد، بهداشت و ایمن سازی محصولات دامی و
خوراک دام دارد.
• تشعشعات هسته ای کاربردهای زیادی در کشاورزی دارد که مهم ترین آنها عبارتستاز:
• موتاسیون هسته ای ژن ها در کشاورزی
• کنترل حشرات با تشعشعات هسته ای
• جلوگیری از جوانه زدن سیب زمینی با اشعه گاما
• انبار کردن میوه ها
112

113. 113
سازمان انرژی
اتمی ایران
مرکز یزد مرکز کرج

114. • در کشاورزی برای افزایش عمر محصولات از مواد شیمیایی استفاده می شود و از سال 2015 به بعد تمام
محصولاتصادراتی باید با استفاده از پرتوها استریل شوند.
• مسئله افزایش عمر نگهداری محصولات کشاورزی نیز در کاربردهای انرژی هست های جای می گیرد و به عنوان
مثال 131 هزار تن خرمای تولیدی فارسبه همین دلیل در نگهداری و بازار رسانی دچار مشکل است.
• با استفاده از پرتودهی م یتوانیم خرمای این استان را بدون استفاده از محصولات شیمیایی از پاتوژن ها عاری
نماییم.
• پسته 11 درصد ازصادرات غیرنفتی ایران را به خود اختصاصداده است، درگیر آفلاتوکسین شده و سالانه 10
درصد پسته ایران به این سم آلوده می شود ولی با استفاده از روشپرتودهی گاما م یتوان این مشکل را حل کرد.
• دفع آفاتگندم و سایر دانه ها
114

115. 1376 • مرکز پرتو فرآیند یزد وابسته به سازمان انرژی اتمی ایران در سال با
هدف تحقیقات و کاربرد پرتوهای الکترون و ایکس که در شتاب دهنده های
ً
15 مختلفتولید میشوند در کیلومتر جاده یزد - تفتدر استان یزد
رسما شروع
بکار کرد.
• در نیمه اول سال 1377 شتاب دهنده الکترون پرقدرت این مرکز پرتودهی
آزمایش ی خود را آغاز نمود.
• پس از طی دوره آزمایش ی این شتاب دهنده از اوایل سال 1378 در جهت ارائه
خدمات پرتودهی به صنایع و انجام پروژه های تحقیقاتی و کاربردی متعدد بکار
گرفته شده است.
115

116. 116
بخش پرتو
فرآیند
واحد پرتودهی
یزد
بخش
آزمایشگاه و
کنترل کیفی
بخش
محصولات
انقباض
حرارتی
بخش پشتیبانی

117. • شتاب دهنده الکترون مرکز پرتو فرآیند یزد از نوع جدید ترین و پرقدرت ترین
موجود در جهان )Rhodotron( شتاب دهنده های با چهار خروجی عمودی
است. این شتاب دهنده از نوع رودوترون و افقی و انرژیهای 5 و 10 میلیون
الکترون ولتمیباشد.
• قدرت نهایی این دستگاه 100 کیلووات است و تا دو برابر قابل افزایشمیباشد
و میتواند پرتوهای ایکسو الکترون تولید نماید.
117

118. • درحال حاضر توان شتاب دهنده مرکز پرتو فرآیند یزد 100 کیلووات و انرژی
آن حداکثر 10 مگا الکترون ولت میباشد که بالاترین انرژی مجاز شتاب دهنده
صنعتی است ، بعبارت دیگر با این سیستم میتوان در هر ساعت حدود 10
مترمکعب محصولاتی مانند لوازم پزشکی را استریل نمود.
118

119. 1. پرتودهی مواد پلیمری :
2. پرتودهی محصولات پزشکی یکبار مصرف :
3. پرتودهی مواد غذایی :
4. کنترل کیفی مواد پلیمری :
5. میکروبیولوژی :
6. انجام پروژه های تحقیقاتی :
7. دزیمتری
119

120. 120
محصولات غذایی مورد تیمار: محصولات خشک شامل حبوبات، ادویه ها و 
سبزیجات
محصولات غیر غذایی: وسایل بهداشتی، پودر بچه، وسایل استریل جراحی، نخ 
های بخیه

121. • خرما: کاهش بار میکروبی و آفات
• انار : مقابله با آفت گلوگاه انار
• سیب: مقابله با کپک پنی سلیوم
• میگو: کنترل ویبریو
• گل های زینتی: از بین بردن آفات و شته، رنگ و شمایل متفاوت
• تولید آنزیمهای گلوکاناز، پکتیناز از قارچها
• افزایش تولید اسید گلوتامیک از کرنی باکتریوم گلوتامیکوم
• تولید اسید آمینه لیزین : کاربرد در مواد غذایی و دامی
• گیاهان دارویی: تولید ترکیبات معطر جدید
• تولید ارقام جدید حاصل از پرتودهی با استفاده از جهش و موتاسیون محصولات کشاورزی یکی از
مباحثی بوده که برای اجرای آن بستر لازم توسط محققان مرکز تحقیقات جهاد کشاورزی فراهم شده
است.
• افزایش توان تولید آستاگزانتین توسط مخمر فافیا که در درمان آب مروارید، آب سیاه و سرطان پستان نقش
دارد
121

122. 122
ارزیابی 2 سال پروژه
یافتن دز
مناسب
بهینه سازی
بررس ی
مشکلات
رادیکال های
آزاد
ارزیابی حس ی

123. • احتمال کاهش رنگ میوه ها و سبزی ها ؛ کاهش رنگ قرمز انار و اثر آنتی
اکسیدانی آن
• ایجاد موتانتهای جدید باکتری و غیر قابل شناسایی بودن آنها
• کامل نبودن زیر ساخت ها،
• کاهش چشمه رادیوایزوتوپ ها و طولانی شدن مدت زمان پرتودهی
• کمبود منابع مالی و تحریم های پیش رو از جمله چالش های این فناوری )تکمیل
مرکز پرتودهی گامای خاورمیانه 110 میلیارد ریال اعتبارنیاز دارد(
123

124. • سامانه پرتودهی چند منظوره گاما در شهرکرد در حال ساخت
• ساخت پرتودهی گاما در شیراز
• پیشنهاد سازمان انرژی اتمی مبنی بر ساخت سامانه پرتودهی در بناب
124

125. • بیشترین کاربرد در ایران:
استرلیزاسیون سرد ادویه ها 
دفع آفات حبوبات 
• آئین كار پرتودهي ادويه 3102
• تجهیزات پرتودهي مواد غذايي – آئین كار كاربرد 8033
125

126. • ماکیان: 7 کیلوگری
• حبوبات: 1 کیلوگری
• ادویه ها و چاشنی ها:
کنترل آفت: 1 کیلوگری 
کاهش بار میکروبی: 10 کیلوگری 
• توت فرنگی: 3 کیلوگری
2 کیلوگری / • شیلات: 2
• گندم: 1 کیلوگری
• سیب زمینی و پیاز: 1 کیلوگری
• خرما: 1 کیلوگری
126

127. Are irradiated foods safe?
YES!
Radiation doses are never large enough to cause
nuclear changes that would cause the food material
to become radioactive.
127

128. So, now would you eat an irradiated food
product?
Why
Or
Why not?
128

129. 129