But according to Tammy Roberts, a nutrition and health education specialist with University of Missouri Extension, there is potential for more food to be irradiated in order to increase the safety of the food supply.
"Irradiation reduces the numbers of harmful bacteria in food including E. coli, Salmonella, and Campylobacter. It is important to note however that irradiation does not take the place of good sanitation and safe food handling," said Roberts.
According to USDA's Food Safety and Inspection Service, food irradiation is a process where approved foods are exposed to radiant energy like x-rays, gamma rays and electron beams.
"Food irradiation is not thought to change the nutritional value of the food any more than other types of processing such as canning," said Roberts. "The flavor change is slight and has been compared to the taste change of unpasteurized milk versus pasteurized milk."
In the United States, food irradiation was first approved in 1963 for wheat flour to control mold. In 1964, irradiation was allowed for potatoes to inhibit sprouting. Other food items approved for irradiation include fruits, vegetables, herbs, spices, meat and poultry.
The most recent approval was for fresh iceberg lettuce and fresh spinach in August of 2008. This decision was made after a food borne illness outbreak caused by contaminated spinach.
According to the United States General Accounting Office, about 97 million pounds of food are irradiated annually. Most of that food, 95 million pounds, is herbs and spices.
"The reason for such a small amount of irradiation is consumers are wary of food irradiation so the food industry only uses it on a limited basis," said Roberts.
Food irradiation is considered safe by several well-respected scientific and health-related organizations including the U.S. Food and Drug Administration, Department of Agriculture, Public Health Service and Centers for Disease Control and Prevention. The American Medical Association, American Dietetic Association and Institute of Food technologists as well as the World Health Organization agree with them.
"If a food is irradiated, it must have a round circle symbol called the radura displayed on the package along with the words 'treated with radiation' or 'treated by irradiation'," said Roberts.
For a detailed discussion of food irradiation go here.