Achievements in Food Irradiation during the 20th Century

Abstract

Developments in food irradiation during the last hundred years can be roughly divided into three periods: First half of the century: Pioneering studies on the use of ionizing radiaton to destroy food spoiling microorganisms and insects. Lack of suitable radiation sources prevents commercial application. 1950 to 1970: Technological studies with the aid of newly available radioisotope sources (Co-60, Cs- 137), electron accelerators (Van de Graaff, linear accelerator and others), and - to a smaller degree - X-rays. Search for optimal conditions of irradiation (radiation dose, packaging, atmosphere and temperature during irradiation) for various purposes (sterilization, pasteurization, insect disinfestation, sprout inhibition of potatoes, onions etc.). Hesitation to use the process commercially, caused by doubts about the health safety of consuming irradiated food. 1970 to 1999: Studies on the wholesomeness of irradiated food, international harmonization of legal regulations, slowly growing commercial application of the process. The years indicated should not be considered as sharp dividing lines. Wholesomeness research was carried out already before 1970 and some technological studies are still going on. A decisive event in the history of food irradiation was the establishment of the International Project in the Field of Food Irradiation (IFIP) in 1970, with the specific aim of sponsoring a worldwide research program on the health safety of irradiated food. Under the sponsorship of FAO, IAEA and OECD, 19 countries joined their resources, with this number later growing to 24. WHO became associated with the International Project in an advisory capacity. The research program included long-term animal feeding studies, short-term screening tests, and the study of chemical changes in foodstuffs irradiated with a dose of up to 10 kGy. The results obtained in the framework of the International Project and in national testing programs were evaluated by the Joint FAO/IAEA/WHO Expert Committee on the Wholesomeness of Irradiated Food (JECFI) in 1976 and 1980. In 1980 this Committee concluded that the irradiation of any food commodity up to an overall average dose of 10 kGy presents no toxicological hazard and no special nutritional or microbiological problems. On this basis the Codex Alimentarius Commission adopted in 1983 a General Standard for Irradiated Foods and a Recommended International Code of Practice for the Operation of Radiation Facilities. National governments and international agencies which had participated in IFIP felt that the international platform for exchange of information on food irradiation provided by the Project since 1970 has been very useful and should be maintained. As a result of these considerations the International Consultative Group on Food Irradiation (ICGFI) was created in 1983, which is now supported by 46 governments. In 1997 an FAO/IAEA/WHO Study Group on High Dose Irradiation examined the results of safety studies carried out on food irradiated with doses higher than 10 kGy. Recognizing that in practice the doses applied to eliminate biological hazard would be below those doses that 2might compromise sensory quality, the Study Group concluded that no upper dose limit need be imposed. Accordingly, irradiated foods were deemed wholesome throughout the technologically useful dose range from below 10 kGy to envisioned doses above 10 kGy. In spite of reassuring research findings and contrary to evaluations by groups of experts, opposition to the practical use of food irradiation is still widespread in several countries. As stated by WHO’s Director General: “Decades of study and practical application have fostered increasing confidence in the ability of food irradiation to protect and preserve food and thereby to safeguard health. WHO is concerned that the unwarranted rejection of this process, often based on lack of understanding of what food irradiation entails, may hamper its use in those countries which may benefit most.” Public opinion about food irradiation was generally positive during the growth period of nuclear technology in the 1950s and 60s. With the advance of the antinuclear movement since the 1970s the climate of opinion has changed. Much more than other modern methods of food processing (microwave heating, extrusion cooking etc.), food irradiation has to overcome barriers created by prejudice, misleading information, restrictive legal and regulatory measures and a resulting reluctance of food manufacturers and food trade to make use of the new technology. Concern about public health problems created by the presence of pathogenic microorganisms in food (Salmonella, Listeria, Campylobacter and others) and the recognition of food irradiation as an effective tool to combat these problems have helped to overcome the barriers. Irradiation of spices to improve their hygienic status is now widely practiced in many countries. The undisputed success of this application will pave the way for other irradiated products.