Invention of Laser is regarded as one of the most significant scientific achievement of the last century. It was variously referred to as "the light fantastic" and "a solution looking for problems". It represents yet another possible but unstable state in which matter can exist by the passage of very strong electric current or highly ionizing radiation through matter. 

When de excitation of molecules and atoms from this unstable state to stable ground state by dissipation of their excess energy takes place in a resonator, monochromatic, coherent light emission - laser - results.

No other method of food processing has been subjected to such a thorough assessment of safety as the radiation processing method. The various aspects of wholesomeness and safety of radiation processed foods have been studied in great detail in scientific laboratories of the world. These results have been reviewed by the experts of the World Health Organization (WHO), Food and Agricultural Organization (FAO), and International Atomic Energy Agency (IAEA) and also independently by the governments of various countries. The tests for wholesomeness and safety of radiation processed food include, checking for induced radioactivity, microbiological safety, safety of chemical changes, nutritional adequacy, and feeding studies on animals and humans. 
At the energies of the gamma rays from Cobalt-60 and those recommended for X-rays and accelerated electrons, no radioactivity can be induced in foods. The microbiological aspects of radiation processed foods have been studied in detail. None of the studies have indicated that foods preserved by radiation pose any special problems in relation to microorganisms. The chemical differences between radiation processed foods and non-irradiated foods are too small to be detected easily. The rough composition of food remains largely unchanged, some losses in certain vitamins may be encountered. Such losses are however also encountered with other methods of food processing. The losses are often minor and could be made up from other sources. Animal feeding studies have been the most time consuming and expensive feature of wholesomeness testing. None of the short- or long-term feeding studies on animals and trials on human volunteers have shown any adverse effects of consumption of radiation processed foods. 

In 1980 a joint FAO/IAEA/WHO Expert Committee on Food Irradiation (JECFI) reviewed the extensive data on wholesomeness collected up to that time and concluded that irradiation of any commodity up to an over all dose of 10 kGy presents no toxicological hazards and introduces no special nutritional or microbiological problems. An Expert Group constituted by WHO in 1994 once again reviewed the wholesomeness data available till then and validated the earlier conclusion of JECFI. The findings are published in the form of a monogram by WHO (WHO, 1994). In 1997 another Expert Group constituted by FAO/IAEA/WHO even affirmed the safety of doses higher than 10 kGy. The Codex Alimentarius Commission, which provides international standards for food has also published Codex General Standard for Irradiated Foods and Recommended International Code of Practice for Operation of Radiation Facilities for Treatment of Foods. 
Radiation processing can be carried out only in facilities licensed to do so. The license could be obtained after fulfilling the requirements of the Atomic Energy Regulatory Board (AERB), an independent regulatory body which looks in to all the safety aspects of a radiation processing plants. In fact a number of facilities for radiation processing of medical products are already in operation in India. 

In India, the Ministry of Health and Family Welfare, amended the Prevention of Food Adulteration Rules (1954) through a Gazette notification dated August 9, 1994, permitting irradiation of onion, potato and spices for internal marketing and consumption. In 1998 a number of other food items were permitted for radiation processing (Table-1a). Approval for additional items including fish and shrimp for shelf-life extension and pathogen control and disinfestation of dry fish and pulse products like besan is expected soon (Table-1b). 

Interest in the practical application of the process is emerging for many reasons. High food losses caused by insect infestation, microbial contamination and spoilage; mounting concern over food borne diseases, harmful residues of chemical fumigants and the impact of these chemicals on the environment, the stiff standards of quality and quarantine restrictions in international trade are some of the reasons. Though irradiation alone can not solve all the problems of food preservation, it can play an important role in reducing post-harvest losses and use of chemical fumigants. 
On the basis of radiation dose, applications of radiation can be classified into:

• Low Dose Applications 

• Medium Dose Applications 

High Dose Applications 

Consumer acceptance is a major factor in commercialization of radiation processing technology. A number of surveys have been conducted nationally and internationally to study the response of consumers to radiation processed food. These surveys as well as limited market trials have demonstrated that consumers are receptive towards radiation processed food. A review on consumer attitudes and market response to food processed by radiation has shown that though consumers express concern about food processed by radiation, when presented with correct information, the acceptance is improved. To evaluate the public perception on radiation processed foods in India, a questionnaire was prepared. Response to tasting of irradiated foods conducted in Mumbai at several seminars organized by Professional bodies, and seminars for specific target groups like University Students, University and School teachers, officers and staff of Army Supply Depot, Mumbai and consumer and food industry groups have shown overwhelming positive response to eating snack items made from irradiated onions, potatoes and spices. The Defence Research and Development Organization (DRDO) have conducted `Ahar Utsavs' with irradiated foods among Defence personnel at several locations in the country with great success. In another study sensory evaluation of irradiated spices was carried out by housewives in Anushaktinagar (DAE staff quarters), college canteens and quantity cookery laboratory of SNDT Women's University, Mumbai. Higher percentage of subjects preferred stored irradiated to stored non-irradiated spices 

Control of food processing in all types of facilities involves the use of accepted methods of measuring the absorbed radiation dose, the distribution of that dose in the product package, and of monitoring of the physical parameters of the process. Dosimetry for food irradiation is analogous to temperature monitoring in thermal processing, with dose meters being the analogs of thermocouples in that they are employed to provide an accurate measure of the rate of energy delivery, total energy delivered or absorbed and the over dose ratio. There are several types of dose meters, the most common ones being based on a chemical change that is linear within a practical dose range. Dosimetry is the keystone of the proper radiation processing. Careful dosimetry is required to ensure that a technologically useful dose has been applied, while maintaining the best possible dose uniformity ratio. Therefore, prior to commissioning of the plant, extensive dosimetric calibrations of the irradiator are carried out and followed during the processing by routine dosimetry. Because it is not possible to distinguish irradiated from non-irradiated products by sight, smell or taste, it is important that appropriate indicator devices which undergo radiation induced colour change be attached to each container/package, and that physical.

The design of the facility and therefore the economics depend on the parameters associated with radiation processing of food. These parameters include dose range, nature of food product, density of product, irradiator efficiency, annual operating hours, throughput, Cobalt-60 loaded, replenishment of Cobalt-60 required and the number of handlers employed, besides capital cost and cost of operation, maintenance, etc . In general a radiation processing facility may cost between 5-10 crores. The cost of processing charged to product is expected to be less than 5% of the cost of the commodity. Past experience has shown enough market demand to sustain this activity.

Expertise and know-how for designing, fabrication and commissioning of irradiators is available in the country with the Department of Atomic Energy and Bhabha Atomic Research Centre. A prototype commercial demonstration irradiator with an initial throughput of 20 tons/day for treatment of spices has been commissioned in Vashi, under the management of Board of Radiation and Isotope Technology (BRIT), a constituent unit of the Department of Atomic Energy. The first prototype commercial demonstration irradiator for potatoes and onions (POTON) with a throughput of 10 tons/h is being set up in Lasalgaon, Nashik Dt., Maharashtra.
Two pilot-plant irradiation facilities, namely the Food Package Irradiator in Food Technology Division, Bhabha Atomic Research Centre and another at the Defence Laboratory, Jodhpur have been licenced for irradiating food items that have been cleared for domestic trade and consumption. It is proposed to use these irradiation facilities for treatment of limited commercial quantities for test marketing and consumer response surveys.

For further information on technology transfer write to:
Head 
Technology Transfer & Collaboration Division 
Bhabha Atomic Research Cenre 
Mumbai-400085

The Joint Expert Committee of the Food and Agricultural Organization (FAO), World Health Organization (WHO), and International Atomic Energy Agency (IAEA), in 1980 concluded that food processed by radiation up to a dose of 10 kGy is safe for human consumption and does not pose any special nutritional, microbiological or toxicological problems. These conclusions have also been reviewed and endorsed later by the similar Joint Expert groups set up from time to time and also by a number of scientific and technical associations and bodies Today over 30 countries world wide, including India, have approved the use of radiation processing of foods for over 100 food items and some of these countries are applying the technology on a limited commercial scale.

1. What is radiation processing of food ? 
2. How irradiation works ? 
3. How do you irradiate food ? 
4. What are the advantages of radiation processing of food ? 
5. Does the irradiation process make food radioactive ? 
6. What is the difference between the terms "Irradiated" and "Radioactive" food ? 
7. What are the chemical changes in radiation processed foods and are they harmful ? 
8. Do the free radicals or radiolytic products which are produced during irradiation affer the safety of food ? 
9. Does irradiation adversely affect the nutritional value of food ? 
10. Does consumption of radiation processed food cause chromosomal abnormalities ? 
11. Are there any human feeding studies of radiation processed foods ? 
12. Can radiation processing of food lead to increased microbiological hazards ? 
13. Can irradiation be used to destroy microbial toxins and pathogenic viruses in food ? 
14. Can irradiation be used to make spoiled food good, or to clean up "dirty foods" ? 
15. Does radiation processing of food that contain pesticide residues or additives present any health hazard ? 
16. Is there any risk in irradiating foods in contact with plastic or other packaging materials ? 
17. Can an accident at a food irradiation facility lead to "Meltdown" of the irradiator and release of radioactivity that would contaminate the environment and endanger people living nearby ? 
18. Do food irradiators have radioactive west disposal problem ? 
19. How irradiation process is controlled to ensure that foods are properly treated ? 
20. Are there any tests to detect whether food has been irradiated ? 
21. Will irradiation increase the cost of food ? 
22. How much a typical radiation processing facility costs ? 
23. Is it true that consumer is opposed to buying radiation processed foods ? 
24. Are radiation processed foods being sold on a regular basis in the market ? 
25. How has the safety of radiation processed food been tested ? 
26. Where cam food be irradiated ? 
27. What is the world status of the technology of radiation processing of food ? 
28. What is the status of the technology of radiation processing of foods in India ? 
29. Why irradiate spices ? 
30. How can radiation processed foods be identified in the market ? 

ANSWERS TO THESE COMMON QUESTIONS