Food Safety Focus (42nd Issue, January 2010) – Food Safety Platform
Safety and Labelling of Irradiated Food
Reported by Ms. Shuk-man CHOW, Scientific Officer,
Risk Assessment Section, Centre for Food Safety
As discussed in the previous issue, irradiation has been proven as an effective food safety measure to protect public health from foodborne infections. Yet, safety of irradiated food continues to attract public concerns.
Safety of Irradiated Food
Research on food irradiation began as early as 1900's. A number of national regulatory authorities and international public health agencies have evaluated the safety of irradiated foods. These include the World Health Organization (WHO), the Food and Agriculture Organization of the United Nations (FAO), the International Atomic Energy Agency (IAEA), and, the U.S. Food and Drug Administration (FDA). These organisations have found that irradiated food treated according to Good Manufacturing Practices (GMPs) is safe for human consumption.
Irradiation process involves passing the food through a radiation field on a conveyor belt at a set speed to control the amount of energy absorbed by the food. The food itself will never come into contact with the radioactive materials of the radiation source, therefore the irradiated food is unlikely to be contaminated with any radioactive substances. To further prevent the occurrence of induced radioactivity, Codex Alimentarius Commission (Codex) and a number of national food safety authorities have set out maximum energy limits for food irradiation to ensure the food is safe for human consumption.
The potential toxicity of irradiated food has been extensively studied through animal and human feeding trials. Data from joint committees of WHO, FAO and IAEA, and other evaluations conducted independently by national expert groups have demonstrated no toxic effects as a result of the consumption of irradiated food.
Toxicity of irradiated food has also been evaluated chemically. It has been shown that treatment with ionizing radiation leads to chemical changes in the resulted food products. These changes, however, are similar in nature and extent to those caused by other conventional processing technologies. There is no evidence that any of the chemical changes caused by food irradiation pose a risk to human health.
Food processing often results in some loss of nutrients and food irradiation is no exception. Nutritional changes in food attributable to irradiation are similar to those result from some heating processes such as cooking and canning. Macronutrients (protein, lipid and carbohydrate) and minerals are not significantly altered by irradiation. However, certain vitamins (e.g. vitamins A, B1 and E) are relatively sensitive to the treatment. In general, the nutrient retention in irradiated food is comparable to that retained in food treated with other preservation techniques. Since irradiated food is normally consumed as part of a mixed diet, consumption of irradiated food will not have a significant adverse effect on our nutritional status.
Labelling of Irradiated Food
Since irradiated food could not generally be distinguished from the untreated counterparts by physical appearance, labelling is essential to ensure consumers' right to make informed choices. Many countries have developed their own national regulations for irradiated food labelling based on the standards set out by Codex. In countries like Canada and USA, irradiated food on sale must carry an international food irradiation symbol and a statement that the product is irradiated. Whereas, in Hong Kong, container containing irradiated food is required to be clearly and legibly labelled with the words "IRRADIATED" or "TREATED WITH IONIZING RADIATION" in English capital lettering and "輻照食物" in Chinese characters.
International food irradiation symbol
Food label of irradiated food available on the market
To monitor compliance with the labelling requirements on food irradiation, regular surveillance is conducted to determine if proper labelling has been made for food products that have been treated with ionizing radiation. From 2001-2008, no non-compliance case was identified.
Readers can find more information about the safety and labelling of irradiated food from the CFS's literature review on "Safety of Irradiated Food".