Proceedings of a symposium jointly organized by the IAEA, FAO and WHO, Aix-en-Provence, 1-5 March 1993. Natural isotopes are among the most powerful tools for investigating past and current environmental changes. The purpose of the symposium was to evaluate the costs and benefits of irradiation for treating various food items either alone or in combination with other processes. The evaluation covered applications of the technology in terms of reducing food losses as well as the possible economic impact of irradiation in controlling or reducing certain food-borne illnesses and in expanding trade in certain food items. Discussion focused on the economic benefits of irradiation to control a number of food-borne diseases, especially those originating from the consumption of food of animal origin, and on the potential economic benefit from radiation as a quarantine treatment for fresh fruits and vegetables.