Research on food irradiation dates back to the early 1900's. Food irradiation was used during World War II to keep food safe for troops. The U.S. Army began to study the use of irradiation on fruits, vegetables, dairy products, fish and meats in the early 1950's. This energy may be in the form of electrons, gamma rays, or x-rays. During irradiation, energy passes through food just as X-rays pass through your teeth and microwaves pass through food when you cook in a microwave oven.
Food irradiation is a way of preserving food, similar to canning or pasteurization.
Like food preservation methods that use heat, irradiation may cause certain chemical changes in food. Irradiation can cause some loss of vitamins and minerals and may cause slight changes in sugars, fats, proteins and enzymes, but no more than in more common methods of food preservation like canning and freezing. The radiant energy used in food irradiation does not cause food to become radioactive. The agency approved the irradiation of wheat and wheat powder in 1963 and white potatoes in 1964. Irradiation is allowed in 35 foreign countries as well.