(From Just Foods)
Food irradiation, a process that became of interest in the 1950s, came mostly in response to much of our food supply being lost to spoilage and insects. Food irradiation exposes food to ionizing radiation to destroy microorganisms that cause spoilage and decomposition and thus the shelf life of the food is extended. Strawberries, for example, that have been irradiated will last two to three weeks longer in the refrigerator. Food irradiation is also used to sterilize food for hospital patients that have severely impaired immune systems. This process can also be used as an alternative to chemical pesticides for controlling insect damage and to control ripening and foodborne illnesses such as Salmonella. Currently, the foods that are approved for irradiation by the U.S. FDA includes meat and poultry, eggs, fruits and vegetables, juices, herbs, spices and flour.
Long-term health consequences of eating irradiated foods are still unknown; however animals fed irradiated foods have died prematurely and suffered mutations, stillbirths, organ damage and nutritional deficiencies. Irradiation has also been linked to cancer in rats and genetic damage in human cells. These effects may be due to byproducts of irradiation, called 2-ACBs, which do not naturally occur in any food.
Irradiation can also change the flavor, odor, texture, color and nutritional content of food. For example, yolks of irradiated eggs are more watery and have less color and brightness than non-irradiated eggs. When radiated at just one-third of the approved level by the FDA, it has been proven that irradiation destroyed the niacin and up to 24 percent of the vitamin A in the egg.
In the US, as in many other countries, irradiated food must be labeled as “Treated with irradiation” or “Treated by radiation” and require the usage of the Radura symbol (as can be seen below) at the point of sale. However, the meaning of the label is not consistent and the amount of irradiation used can vary. For more information, view the Wikipedia entry.