Irradiation is the use of radiation from x-rays or radioactive materials on food. The process sterilizes food and kills bacteria. The benefits of irradiating food include the ability to control insects and bacteria, such as
Salmonella. The process can give foods (especially fruits and vegetables) a longer shelf life and cause less
But the topic of irradiation seems to be one surrounded by as much myth as fact. For example, food irradiation does not make the food radioactive, nor will it make you glow in the dark. In fact, it can actually prevent you from taking on the greenish-tinge that comes with food poisoning.
Food irradiation, like pasteurization or canning, is a food safety technology designed to eliminate the germs, bacteria, and parasites that would otherwise cause foodborne diseases from the foods we eat. It is used in many other countries beyond the United States (eg, China, Russia, Portugal), and the World Health Organization (WHO) and government agencies support the use of irradiation.
According to the Center for Food Safety and Applied Nutrition, there are four main purposes of food irradiation:
- Preservation—Irradiation extends the shelf life of a food by destroying or inactivating organisms in the food that may cause spoilage and decomposition.
Sterilization—Because of the sterilization process, these foods can be given to people with severely-impaired immune systems. In addition, both NASA and the military use irradiated food as a means of preventing foodborne illness.
- Reduce sprouting, ripening, and damage from bugs—Irradiation is sometimes used in place of chemicals to prevent damage to food. This process is particularly useful for products like potatoes, tropical and citrus fruits, grains, spices, and seasonings.
- Reduce foodborne illness—Irradiation destroys organisms, like Salmonella.
The process can involve these technologies:
- Gamma rays—a radioactive element (cobalt 60 or cesium 137) is used to irradiate the food; can be used with very thick foods
- Electron beams—a stream of high-energy electrons are shot through an electron gun; used to treat foods that are not very thick
- X-ray irradiation—electrons are sent through a metal plate to create a x-rays on the other side of the plate; can be used with thick foods
Despite some of the myths you may have heard, food irradiation does not change the nutritional value of the food or make it dangerous to consume. Some foods may be slightly warmed by the process, and others may taste somewhat different. (Imagine the difference in taste between pasteurized and unpasteurized milk). Afterwards, food that has been irradiated needs to be handled (eg, stored and cooked properly) in the same way that you would any other food.
In general, the changes to food caused by the irradiation process are so minimal that distinguishing an irradiated food from a nonirradiated food can be difficult. In the US, all manufacturers of irradiated foods are required to put an international symbol, called the
on their products and to include a description of the process on their product labels.
It is important to remember, however, that purchasing irradiated food is no guarantee of its safety. Food irradiation does not replace proper food production, processing, handling, or preparation, nor can it enhance the quality of or prevent contact with foodborne bacteria after irradiation. Therefore, the rules of basic food safety must still be followed:
- Raw meat, fish, poultry, and dairy products should be as fresh as possible at the time of purchase. Buy products with the longest shelf life.
- Place raw meat, poultry, and fish away from any cooked foods or fresh produce in the grocery cart.
- Store refrigerated foods below 40°F.
- Wash hands before, during, and after food preparation.
- Store all leftovers within one hour by placing them in tightly sealed, shallow containers.
- Eat leftovers within 3-4 days for safety.
Food irradiation. American Dietetic Association. Available at:
. Accessed December 15, 2003.
Frequently asked questions about food irradiation. Centers for Disease Control and Prevention website. Available at:
. Accessed May 11, 2011.
Loaharanu P. Irradiated foods. American Council on Science and Health website. Available at: . Published July 3, 2007. Accessed May 9, 2011.
Handling your food safely. American Dietetic Association website. Available at:
. Accessed December 15, 2003.
Irradiated foods. American Council on Science and Health website. Available at:
. Accessed October 14, 2007.
Last reviewed May 2011 by Brian Randall, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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