IRRADIATIONAPPLICATIONS & ADVANCES

ByMastan Vali K16FT1D7821

Irradiation?• Irradiation is the process by which an object is exposed to radiation.• The exposure can originate from various sources including natural sources.• Most frequently Ionizing Radiation.• Irradiation processing of food involves the controlled application of energy from

ionizing radiations such as ɣ-rays, X-rays and electrons for food preservation.• ɣ-rays are emitted by radioisotopes such as Cobalt-60 & Caseium-137.• Electrons & X-rays are generated by machines using electricity.• Being a cold process Irradiation can be used to pasteurize and sterilize foods

without causing changes in freshness and texture of food unlike heat.• Unlike chemical agents, irradiation does not leave any harmful toxic residues in

food.• Food absorbs energy when it exposed to ionizing radiation (absorbed dose), which

is measured in Grays (Gy), KiloGrays (Kgy).• A Gray is a unit of energy equivalent to 1 J/Kg.

India - Irradiation• India is a large producer of radioisotopes. The radioisotopes are produced in the

research reactors at Trombay, accelerator at Kolkata and various nuclear power plants.

• BARC, BRIT and VECC are the organizations of DAE which are engaged in the development of radiation technologies and their applications in the areas of health, agriculture, industry and research.

• DAE is working in close co-operation with other organizations of the Government of India to widen the reach of these technologies for the benefit of the common man.

• Remarkable progress was achieved in applications of Radioisotopes and Radiation Technology in the areas of nuclear agriculture, food preservation and industry.

Note: BARC - Bhabha Atomic Research Centre, Trombay, Mumbai. VECC - Variable Energy Cyclotron Centre, Kolkata. DAE - Department of Atomic Energy, Mumbai. BRIT – Board of Radiation and Isotope Technology, Mumbai

India - Irradiation• KRUSHAK (Krushi Utpadan Sanrakshan Kendra), a technology demonstration

unit of BARC, set up for low dose applications of radiation for food preservation became operational at Lasalgaon near Nashik. The plant radiation processed onion, pulses, rawa and turmeric.

• Radiation Processing Plant, Vashi operating since January 2000, performed very well with an enlarged scope of processing of products. 

• The major thrust given to the area of setting up of new radiation processing plants for medical, food related and allied products has shown very encouraging results in the recent times and about eight private parties signed the MoU with BRIT for setting up new plants. The first of these (M/s. Organic Green Foods Ltd., Kolkata) is expected to be operational shortly.

• BRIT also developed an install-and-operate type irradiator for radiation processing of food items. The plant was undergoing evaluation tests. 

• DAE is working with the Ministry of Health for notifying items for radiation processing for approval of additional items and other related issues.

1. Applications at low dose levels (10Gy-1kGy)

• Sprouting of potatoes, onions, garlic, shallots, yams etc., can be inhibited by irradiation in the dose range 20-150Gy.

• Ripening of fruits can be delayed in the dose range 0.1-1kGy.• Insect disinfestations by radiation in the dose range of 0.2-1kGy is used to

prevent the losses caused by insect pests in stored grains, pulses, cereals, flour, coffee beans, spices, dried fishery products, etc.,

• The inactivation of some pathogenic parasites such as tapeworm and trichina in meat can be achieved at dose range of 0.3-1kGy.

2. Applications at Medium Dose levels (1-10kGy)

• Radiation enhances the keeping quality of certain foods through a substantial reaction in the number of spoilage causing MO’s.

• Fresh meat, seafood, fruits & vegetables may be exposed to such treatments with doses ranging from 1-10kGy.

• This medium dose application is very similar to heat pasteurization, known as Radiopasteurization.

• Extension of shelf life of fresh fish, strawberries, mushrooms etc., 1-3kGy.• Elimination of spoilage & pathogenic MO’s 1-7kGy in fresh and frozen seafood,

poultry, meat, etc.,• Improving technological properties of food 2-7kGy for Grapes (increasing juice

yield), dehydrated vegetables (reduced cooking time), etc.,

3. Applications at high dose levels (10-100kGy)

• Irradiation at doses of 10-30 kGy is an effective alternative to the chemical fumigant ethylene oxide for microbial decontamination of dried spices, herbs and other dried vegetable seasonings.

• Radiation sterilization in the dose range 25-70 kGy extends the shelf life of precooked or enzyme inactivated food products in hermetically sealed containers, known as Radappertization.

• 30-50 kGy used for Industrial sterilization of meat, poultry, seafood, etc.,• 10-50kGy is applied for decontamination of spices, enzyme preparations, natural

gum.• Multi-laminate packaging structure of polymers like nylon, PVC, cellophane, PE

& Polyester are used as a prominent barrier material in packaging of irradiated food (Agarwal, S.R. and Sreenivasan, A. 1972).

HISTORY and ADVANCES• The discovery of x-rays by W.K. Roentgen in 1895 and the discovery of radioactive

substances by H. Becquerel in 1896 led to intense research of the biological effects of these "radiations."

• Initially, most of the irradiations made use of x-rays, which are produced when electrons from an electron accelerator are stopped in materials.

• These early investigations laid the foundation for food irradiation (Brynjolfsson, 1989). • Ionizing radiation was found to be lethal to living organisms soon after its discovery. • However, no commercial development of this use occurred then, due to the inability to obtain

ionizing radiation in quantities needed and at costs that could be afforded (Urbain, 1989).• They considered x-rays to be impractical because of the very low conversion efficiency from

electron to x-ray that was possible at that time. • Ultraviolet light was considered to be impractical because of their limited ability to penetrate

matter. • Neutrons exhibited great penetration and were very effective in the destruction or inactivation

of bacteria, but were considered inappropriate for use because of the potential for inducing radioactivity in food.

• In the mid 1940s, the interest in food irradiation was renewed when it was suggested that electron accelerators could be used to preserve food.

• From 1940 through 1953, exploratory research in food irradiation in the United States was sponsored by the Department of the Army, the Atomic Energy Commission, and private industry (Thayer, 1986).

• Early research in the late 1940s and early 1950s investigated the potential of 5 different types of radiation (ultraviolet light, x-rays, electrons, neutrons, and alpha particles) for food preservation.

• Researchers concluded at that time that only cathode ray radiation (electrons) had the necessary characteristics of efficiency, safety, and practicality.

• In the 1940s, as described by Urbain (1989), sources of proper kinds of ionizing radiation became available.

• The first sources were machines that produced high energy electron beams of up to 24 million electron volts.

• This energy was sufficient to penetrate and sterilize a 6-inch No. 10 can of food when electron beams were "fired" from both sides of the can.

• Also in this same decade, man-made radionuclides such as Cobalt-60 and Cesium-137 (which in their radioactive decay emit gamma rays) became available through the development of atomic energy.

• The availability of these sources stimulated research in food irradiation aimed at the development of a commercial process.

• Proctor and Goldblith (1951) concluded that food could be sterilized by ionizing radiation. They reported a number of important observations.

1. The medium in which microorganisms were irradiated was a factor in determining the correct dose of radiation for bacterial inactivation.

2. Enzymes were more resistant to ionizing radiation than were bacteria.3. Irradiation in the frozen state minimized the development of off- flavour in milk and

orange juice.• Because of military interest in this type of food processing, much of the early research was

done to sterilize food by the Quartermaster Corps of the U.S. Army at the Food and Container Institute in Chicago.

• The Army Quartermaster Corps concluded early on that wholesome, economical, shelf-stable field rations could be provided through irradiation.

• However, early sensory evaluation of sterilized irradiated meats described it as having a "wet dog aroma."

• The development of off-flavors and aromas in meats was solved by freezing meat to -22ºC (-30ºF). 

• The reduction of spores of proteolytic A and B strains of Clostridium botulinum.

• Research was continued by the U.S. Army when a food irradiation facility was built at the Army's research laboratories in Natick, Massachusetts in 1962.

• The U.S. Army maintained its interest in high-dose irradiation sterilization of meat products.

• The responsibility for low-dose pasteurization applications development was transferred to the AEC (Atomic Energy Commission).

• The Army sponsored studies for the development of shelf-stable bacon, ham, pork, beef, hamburger, corned beef, pork sausage, codfish cakes, and shrimp.

• In 1980, the residual Army food irradiation program (chicken) was transferred to the U. S. Department of Agriculture (USDA).

• Pasteurization is best defined as reducing the existing numbers of vegetative pathogenic cells to an undetectable level, less than 1/gram. 

• Since the maximum load of vegetative pathogens such as Salmonella spp. is on the order of 103/gram, this is the standard that is usually used.

Food Irradiation: Some Major Milestones  1895 Von Roentgen discovers x-rays. 

 1896 Becquerel discovers radioactivity. Minsch publishes proposal to use ionizing radiation to preserve food by destroying microorganisms. 

1904  Prescott publishes studies at MIT on bactericidal effects of ionizing radiation. 

1905  U.S. and British patents issued for use of ionizing radiation to kill bacteria in foods. 

1905 to 1920 Much research conducted on the physical, chemical, and biological effects of ionizing radiation. 

1921 USDA researcher Schwartz publishes studies on the lethal effect of x-rays on Trichinella spiralis in raw pork. 

1923  First published results of animal feeding studies to evaluate the wholesomeness of irradiated foods. 

1930  French patent issued for the use of ionizing radiation to preserve foods. 

1943 MIT group, under U.S. Army contract, demonstrates the feasibility of preserving ground beef by x-rays. 

Late 1940s and early 1950s 

Beginning of era of food irradiation development by U.S. Government (among Atomic Energy Commission, industry, universities, and private institutions) including long-term animal feeding studies by U.S. Army and Swift and Company. 

1950  Beginning of food irradiation program by England and numerous other countries. 

Regulations for Food Irradiation • The 1958 Food Additive Amendment to the Food, Drug and Cosmetics Act required advance approval

from the Food and Drug Administration (FDA) before any particular irradiated food could be sold publicly.

• At this time, irradiation was legally defined as an additive, not a process (IFT Expert Panel, 1983).• The FDA, in 1963 and 1964, approved the use of low-dose ionizing radiation for bacon, for killing

insects in wheat and wheat flour, and for the inhibition of sprouting in potatoes. • In 1983, the FDA approved sterilization of spices with ionizing radiation. • Low-dose irradiation can also be used to inhibit sprouting of onions, garlic, and ginger, and to inhibit the

ripening of bananas, avocados, mangoes, papayas, and guavas. • In 1985 and 1986, the USDA Food Safety and Inspection Service and the FDA approved the processing

regulations for treatment of pork meat and products with a minimum dose of 0.3 kGy and a maximum of 1.0 kGy (1 kGy = 100 kilorads) of ionizing radiation to control Trichinella spiralis.

• From 1990 through 1992, the U.S. government announced approval of ionizing radiation treatments of poultry to eliminate foodborne pathogens.

• The regulation for irradiation of poultry products from the USDA Food Safety and Inspection Service requires minimum and maximum doses of 1.5 and 3.0 kGy respectively.

• Most recently, the Food Safety and Inspection Service of the USDA has indicated acceptable levels of ionizing radiation for processing red meat products (beef, veal, and lamb) to the FDA.

• A maximum level of 4.5 kGy is proposed for unfrozen red meat, and 7.5 kGy for frozen red meat. • Approval of radiation treatment for ground meat products (and other meat items) in 1995.

Applications of Food IrradiationType of Food Radiation Dose in kGy  Effect of Treatment 

Meat, poultry, fish, shellfish, some vegetables, baked goods,

prepared foods 20 to 71 

Sterilization. Treated products can be stored at room temperature without spoilage. Treated products are safe for hospital patients who require microbiologically sterile diets.

Spices and other seasonings  Up to a maximum of 30 Reduces number of microorganisms and insects. Replaces

chemicals used for this purpose. Strawberries and some other

fruits  1 to 5  Extends shelf life by delaying mold growth.

Grain, fruit, vegetables, and other foods subject to insect

infestation 0.1 to 2 

Kills insects or prevents them from reproducing. Could partially

replace post-harvest fumigants used for this purpose. 

Bananas, avocados, mangoes, papayas, guavas, and certain

other non-citrus fruits 1.0 maximum  Delays ripening. 

Potatoes, onions, garlic,

ginger  0.05 to 0.15 Inhibits sprouting. 

Grain, dehydrated vegetables, other foods Various doses  Desirable changes (e.g., reduced rehydration times).

Applications of Food IrradiationType of Food Radiation Dose in kGy Effect of Treatment

Meat, poultry, fish, shellfish, some vegetables, baked goods, prepared foods

20 to 71 Sterilization. Treated products can be stored at room temperature without spoilage. Treated products are safe for hospital patients who require microbiologically sterile diets.

Spices and other seasonings Up to a maximum of 30 Reduces number of microorganisms and insects. Replaces chemicals used for this purpose.

Meat, poultry, fish 0.1 to 10 Delays spoilage by reducing the number of microorganisms in the fresh, refrigerated product. Kills some types of food poisoning bacteria and renders harmless disease-causing parasites (e.g., trichinae).

Strawberries and some other fruits 1 to 5 Extends shelf life by delaying mold growth.

Grain, fruit, vegetables, and other foods subject to insect infestation 0.1 to 2

Kills insects or prevents them from reproducing. Could partially replace post-harvest fumigants used for this purpose.

Bananas, avocados, mangoes, papayas, guavas, and certain other non-citrus fruits

1.0 maximum Delays ripening.

Potatoes, onions, garlic, ginger 0.15 to 0.30 Inhibits sprouting. Grain, dehydrated vegetables, other foods Various doses Desirable changes (e.g., reduced rehydration times).

Approximate Killing Doses of Ionizing Radiations in kGyOrganism 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 11Bacteria (cells of pathogens):  

      Mycobacterium tuberculosis         Staphylococcus aureus         Cornybacterium diphtheriae         Salmonella spp.

1.41.4 to 7.0

4.23.7 to 4.8

Bacteria (cells of saprophytes):         Gram-negative:

             Escherichia coli               Pseudomonas aeruginosa               Pseudomonas fluorescens               Enterobacter aerogenes 

1.0 to 2.31.6 to 2.31.2 to 2.31.4 to 1.8

      Gram-positive

            Lactobacillus spp.               Streptococcus faecalis               Leuconostoc dextranicum               Sarcina lutea

0.23 to 0.381.7 to 8.8

0.93.7

Bacterial spores:  

      Bacillus subtillus         Bacillus coagulans         Clostridium botulinum (A)         Clostridium botulinum (E)         Clostridium perfringens         Putrefactive anaerobe 3679        Bacillus stearothermophilus

 12 to 1810

19 to 3715 to 18

3.123 to 5010 to 17

Wholesomeness of Irradiated Foods 

• The World Health Organization (WHO) (as cited by Lee, 1994) released the following updated policy statement on September 23, 1992: "Irradiated food produced under established Good Manufacturing Practices is to be considered safe and nutritionally adequate because:

1. The process of irradiation will not introduce changes in the composition of the food which, from a toxicological point of view would impose an adverse effect on human health.

2. The process of irradiation will not introduce changes in the micro flora of the food which would increase the microbiological risk to the consumer.

3. The process of irradiation will not introduce nutrient losses in the composition of the food which, from a nutritional point of view, would impose an adverse effect on the nutritional status of individuals or populations.

• America's astronauts have been eating irradiated foods from the beginning of the space program. Irradiated food was eaten by the Apollo astronauts on the moon and on the joint American-Soviet Apollo-Soyuz space flight. American astronauts have continued to consume irradiated beef, pork, smoked turkey and corned beef aboard the space shuttle flights.

• Review of data and concerns raised during the Food and Drug Administration and Food Safety Inspection Service of the USDA approval process for irradiation of poultry indicates that properly processed irradiated foods are wholesome.

• In a feeding trial in China, 21 male and 22 female volunteers consumed 62 to 71% of their total caloric intake as irradiated foods for 15 weeks (Chi et al., 1986). The diet included rice irradiated to 0.37 kGy and stored for 3 months; rice irradiated to 0.4 kGy and stored for 2 weeks; meat products such as pork sausage irradiated to 8 kGy and stored at room temperature for 2 weeks; and 14 different vegetables irradiated to 3 kGy and stored at room temperature for 3 days. A double-blind design was used and included measurement of total caloric intake, monthly biochemical and physical exams and sensory evaluations of the food. The diet was well received, and there were no adverse findings associated with the consumption of the irradiated foods.

• Bhaskaram and Sadasivan (1975) reported that children suffering from kwashiorkor developed a 1.8% incidence of polyploidy after being fed irradiated wheat. It was also reported that there was 0% polyploidy in controls and a test group of children after the removal of the treated diet, even though polyploidy is not unusual in human populations.

• Polyploidy describes cells, tissues, or individuals in which there are 3 or more sets of chromosomes.• There is a concern that ionizing radiation creates free radicals, and that they may be present in the food

at the time of ingestion. Free radicals are also formed when food is fried, baked, ground, and dried. More free radicals are created during the toasting of bread than through ionizing radiation. In foods with a high moisture content, free radicals disappear within a fraction of a second; in dry foods, the free radicals are much more stable and do not dissipate as quickly (ACSH, 1988; Jones, 1992).

HISTORY OF LABELLING• Labelling of foods treated with ionizing energy has been one of the most

controversial issues related to commercial production. • The Joint FAO/IAEA/WHO Expert Committee concluded that for irradiated foods

which had been approved as safe to eat, there was no valid scientific reason for identifying the products with a label at the retail level when similar labelling is not required for the other commonly used processing methods (WHO, 1981).

• The United Nation’s Codex Alimentarius Commission, after receiving the recommendations of the Joint FAO/IAEA/WHO Expert Committee, referred the labelling issue to its Committee on Labelling. This committee, which meets every 2 years, usually in Ottawa, Canada, is concerned with uniformity in labelling among the approximately 130 Codex member countries, including Canada and the United States, to facilitate international trade.

• The committee agreed to recommend that the use of a logo or symbol be optional, but that the label of an irradiated food should carry a written statement indicating that it had been irradiated.

ADVANTAGES OF THE IRRADIATION

• The World Health Organization (WHO) (1987) summarizes advantages of the irradiation technique over conventional food processing methods in this manner:

1. Foods can be treated after packaging.2. Irradiation processing permits the conservation of foods in the fresh state.3. Perishable foods can be kept longer without noticeable quality loss.4. The cost of irradiation and the low energy requirements compare

favourably with conventional food processing methods. Irradiation treatment up to the prescribed dose leave no residue; changes in nutritional value (i.e., loss of some vitamins) are comparable with those produced by other processes and during storage.

5. Foods processed under prescribed conditions for irradiation do not in any way become radioactive, a fact that many people do not understand.

Changes occurring in nutrients caused by food irradiation

Food Components Alteration

Carbohydrates Hydrolysis and oxidative degeneration

Proteins Denaturation, deamination and oxidation of sulfhydryl and aromatic group

Fats Autooxidation, Polymerization, dehydration

Note: Changes made by irradiation are so minimal that it is not easy to tell if a food has been irradiated(U.S.FDA)

Case studies

Irradiated sliced green onions at doses ranging from 0.5 to 3 kGy

Doses greater than 1.5 kGy caused loss of aroma and visual

quality

Lower doses of radiation (0.5, 1.0 and 1.5 kGy) reduced

bacterial loads

While colour, texture and aroma were preserved

Fan et al. (2003)

• Irradiated 13 types of fresh-cut vegetables at dosages ranging

from 0.5 to 3 kGy

• Measured tissue damage by electrolyte leakage

• Green onions, celery, red lettuce and carrots were the most

sensitive

• Broccoli, endive and red cabbage were the most resistant

Fan and Sokorai (2005)

• Spinach, romaine lettuce, iceberg lettuce, parsley and green

leaf lettuce were intermediate in sensitivity

Fan and Sokorai (2005)

• Irradiation improves the nutrient content of lettuce

• The irradiated lettuce showed greater browning than controls

• Effect of the increased phenolic content

Fan et al.,(2005)

• Irradiation doses greater than 1 kGy caused softening (loss of

crispiness), browning and decreased vitamin C content in lettuce

• When lettuce irradiated at 0.5 and 1.0 kGy was dipped in hot

water at 47oC

• Reduced bacterial loads without effects on vitamin C content

(Fan et al. 2003)

Other Purposes Of Irradiation Technology

• In addition to Food Processing, irradiation is used for many purposes, including: cancer treatment, performing security checks on hand luggage at airports, making tires more durable, sterilizing manure for gardens, making non-stick cookware coatings, purifying wool, sterilizing medical products like surgical gloves, and destroying bacteria in cosmetics.

COMMERCIALIZATION OF IRRADIATED FOODS

• Until recently, only irradiated dried spices and enzymes were marketed in the United States. In January 1992, irradiated Florida strawberries were sold at a North Miami supermarket. Sales of irradiated products are on-going in several grocery stores. Poultry irradiation began commercially in 1993.

• The largest marketers of irradiated food are Belgium and France (each country irradiates about 10,000 tons of food per year), and the Netherlands (which irradiates bout 20,000 tons per year).

What Products can’t be Irradiated?• All Liquid Products with sugar in them and Milk, etc.,

International Acceptance• Today, over 42 countries in the world including developed

countries like USA, Canada, UK, France as well as developing countries like India, Bangladesh and Thailand have given clearance for radiation processing of food for over 100 food items and about 30 of them are applying the technology on a limited commercial scale.

Indian Acceptance• In 1994 the Govt. of India amended the Prevention of Food Adulteration Act

(1954) Rules and approved irradiation of onion, potato and spices for domestic market.

• Additional items were approved in 1998 and 2001. In India, Bhabha Atomic Research Centre (BARC) has done extensive R&D work on preservation of food by radiation.

• Board of Radiation and Isotope Technology (BRIT) has established facility for radiation processing of foods at Navi Mumbai.

• BARC has also set up a plant for radiation processing of onions and potatoes at Lasalgon in Nasik District of Maharashtra.

• The Ministry of Food processing Industries is now encouraging entrepreneurs for setting up of facilities for radiation processing of food in private sector.

• It is quite heartening to note that several private entrepreneurs have come forward in setting up of radiation processing plants in the country.

Consumer Acceptance• The majority of food irradiation opposition will not usually buy irradiated food,

of course. Actually, the majority of the oppositions is getting small due to the explanation the food irradiation has nothing to do with chemicals or chemical residues.

• Even though, if compare to other preserved food, irradiated food still sold in small volume, in the US, irradiated hamburger, Hawaiian papaya and sweet potato have been successfully sold for at least a decade as well as exotic fruits from Mexico and Asian nations became available.

• Internationally beside the US, there are some examples around the globe where irradiated food became successful.– New Zealand: irradiated mango and litchi have been imported and sold since 2005– France and Belgium: irradiated frog legs– Thailand: irradiated fermented sausage– China: irradiated spicy chicken feet

• Based on the author’s personal surveys, there 2 minorities which one of them just reject the food and another one is actively interesting in the food. The majority’s decisions are depending on several factors

Technology - Companies• Agrosurg Irradiators India Pvt Ltd, Vasai, MH

http://www.agrosurg.com/acrediation.html • AV Processors Pvt Ltd, Mumbai,

http://www.sterico.com/

NSPM:- National Standard For Phytosanitory Measures

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