Radiation processing of foodstuffs

PTI FEATURE (March 3, 2012) SCIENCE/ PF-35/2012                                                                                                                                                                                          Radiation processing of foodstuffs

Dr.K.S.Parthasarathy

The International Atomic Energy Agency (IAEA) reports that food irradiation is approved for use in over 55 countries worldwide. IAEA noted that some 20 countries, including Argentina, Australia, Bangladesh, Thailand, the USA and Vietnam have legislation allowing phyto-sanitary uses of irradiation.

Keep away a handful of green-gram; after a few days, you may see tiny beetles emerging out of them. Insects lay egg during the flowering season. The ova develop in to mature insects. Almost all pulses and cereals in India are infested. There is no easy way to remove the bug. Insecticides are ineffective as it cannot reach them. An effective method is to expose the infested seed to ionising radiation. Radiation penetrates the seeds and kills the bug.  

Food Irradiation is the treatment of food by ionising radiation. The process greatly reduces, but does not eliminate, bacteria. Food irradiation is unpopular because of the mistaken notion that irradiated food is radioactive. Gamma rays from Cobalt 60, electron of 10 million electron volts if X-rays of 5 million are the only types of radiation approved for use in the process. These radiations will not make food radioactive.

The American Dietetic Association, The American Council on Science and Health, American Medical Association, the American Council on Science and Health, the American Medical Association, the Council for Agricultural Science and Technology, the International Atomic Energy Agency, the Institute of Food Technologists, the Scientific Committee of the European Union, the United Nations Food and Agricultural Organisation and the World Health Organisation have endorsed the process.

Approval for the process came after 40 years of scientific research and testing. Food scientists have not studied any other food technology more extensively.

The American Dietetic Association stated that people requiring the safest food, hospital patients, receiving bone marrow transplants are routinely given irradiated foods. Spices, being of tropical origin, are often microbe-laden. Irradiated spices are preferred for routine use in hospital food service for patients.

Contaminated food causes food poisoning. Often, the symptoms of food poisoning are mild. Rarely, it may be fatal. The concern over the prevalence of food-borne diseases is mounting. The US Food and Drug Administration recognised that irradiation is the only known method to eliminate deadly bacteria in raw meat.

Precise data on food-borne diseases from different countries are not available. The US Centres for Disease Control (CDC) estimates that each year roughly 1 in 6 Americans (or 48 million people) gets sick, 128,000 are hospitalized, and 3,000 die of food-borne diseases.

Bacteria thrive in meat. Harmful E-coli is beastly; it causes hemorrhagic colitis leading to high fever, vomiting and bloody diarrhoea. The patient is dehydrated. If the patient has weakened or immature immunity system, the disease may progress to kidney damage. Six per cent of such patients die.

On February 22, 2000, US FDA issued final rule which permitted using radiation to refrigerated or frozen uncooked meat or meat products to reduce levels of food-borne pathogens and to extend shelf life.

The International Atomic Energy Agency (IAEA) reports that food irradiation is approved for use in over 55 countries worldwide. IAEA noted that some 20 countries, including Argentina, Australia, Bangladesh, Thailand, the USA and Vietnam have legislation allowing phyto-sanitary uses of irradiation.

Irradiation is useful in preservation of food, control of sprouting of items such as potato and onion and control of food-borne diseases. Irradiation destroys or inactivates organisms that cause spoilage thereby extending shelf life of certain foods. But foods must be kept in airtight bags to prevent re-infestation.

The process is energy efficient. It does not leave any residue. The products remain closer to the fresh state in flavour, colour and texture. The chemical change in food due to irradiation is so small that it is difficult to design a test to identify whether a food has been irradiated. During the process, no liquid is added; it does not cause loss of natural juices. Large or small amounts of foods can be irradiated in appropriate containers.

Food irradiation is essentially a cold process. Because of this, nutrient losses are significantly less than those associated with canning, drying and heat pasteurisation. Macronutrients such as carbohydrates, proteins and fats undergo little change during irradiation

The European Committee for Standardisation of the European Commission has published six standards to identify irradiated food. Irradiated food containing fat can be identified by gas chromatic analysis of hydrocarbons. If irradiated food contains cellulose or bone or crystalline sugar, electron spin resonance spectroscopy is used. Spices may contain traces of silicate minerals. Thermo-luminescence of the silicate fraction is useful to identify irradiated spices. More sophisticated methods such as photo-stimulated luminescence, DNA comet assay are also used in the case of some foods.

            A system of carefully designed interlocks ensures that no person can enter the radiation area when the sources are exposed. The staffs employed at the facility are well trained and qualified. They follow diligently prepared operating procedures. The Atomic Energy Regulatory Board (AERB) inspects the facility periodically and reviews the safety reports from the radiological safety officer. The radiation doses to workers in the facilities are only small fractions of the limit prescribed by AERB.

The Atomic Energy (Control of Irradiation of Foods) Rules 1996 and the Prevention of Food Adulteration (Fifth Amendment) Rules 1994 and other rules and notifications issued from time to time are the applicable rules for commercial irradiation of food in India.  The Department of Atomic Energy (DAE) and the Atomic Energy Regulatory Board enforce the former rules. DAE licenses the irradiator after AERB issues a certificate of approval. Before this, inspectors from AERB ensure that the installation satisfies all the prescribed safety requirements. The AERB is empowered to withdraw the certificate of approval if it is found necessary. AERB inspectors inspect the facilities periodically.

The DAE has licensed 17gamma irradiation facilities so far. More facilities are being planned in the near future. AERB has standardised the procedure to issue certificate approvals to the applicants. Wrong notions have come in the way of achieving progress in the commercial use of irradiation. Consumer acceptance of the technology shall improve when they are informed about the facts about this unique technology. If I have a choice, I shall eat only irradiated food. I know that they are safe.