Nutritional and other implications of irradiating meat.

Different methods have been developed to extend the shelf-life of meat and its products ranging from the traditional use of salt to canning, freezing and modified-atmosphere packaging. As well as these more conventional approaches to meat preservation, the use of ionizing radiation has also been extensively studied over many years. The irradiation sources which are permitted for use with food are gamma photons from 6oCo or 137Cs, high-energy electrons generated by machines, maximum energy 10 MeV and X-rays with a maximum energy of 5 MeV (Codex Alimentarius Commission, 1984). At doses of about 25-50 kGy, irradiation can be used to achieve sterilization and in the 1960s shelf-stable radiation-sterilized meat products were developed to substitute for canned or frozen military rations. Currently, sterile meals are produced for immunocompromized patients using irradiation. With doses below 10 kGy, the process is effective in enhancing food safety through the inactivation of pathogenic microorganisms such as Salmonella and Campylobacter and extending shelf-life by eliminating the micro-organisms responsible for normal spoilage. Following the report of the Food and Agriculture OrganizatiodInternational Atomic Energy Agencymorld Health Organization Joint Expert Committee on the Wholesomeness of Irradiated Food (1981) which concluded that 'irradiation of food up to an overall average dose of 10 kGy produced no toxicological hazard and introduced no special nutritional or microbiological problems', there has been renewed interest in the use of lower doses of irradiation for the preservation of food. In 1991, the UK government introduced new regulations permitting the irradiation of seven categories of food, including chicken, under strictly controlled conditions (UK Government Regulations, 1 9 9 0 ~ ) . Currently, thirty-seven countries have approval for the irradiation treatment of a range of foods or food items and of these countries, twenty-six are using the process on a commercial scale (P. Loaharanu, personal communication).