radiation approved for commercial use, but many
viruses cannot.
Irradiating foods does not make the foods radio-
active in any way. Irradiation done using beams of
high-energy electrons or X-rays do not even use any
radioactive material. Irradiation done using gamma
rays involves exposure of the food to a radioactive
substance, usually cobalt 60 or cesium 137, for a short
period. The radioactivity of this substance is not in any
way transferred to the food that is exposed to it.Precautions
Irradiation is not a substitute for safe food han-
dling practices. Although irradiation kills or disables
many pathogenic organisms, these organisms can be
reintroduced to the foods if cross contamination
occurs. In addition, not every pathogen is completely
destroyed by irradiation, and leaving foods such as
raw meat out at room temperature can allow these
pathogens to reproduce to significant levels. Irradia-
tion should be viewed as an extra step to help ensure
that the food supply is safe, not as a replacement for
food safety practices that are already in place.Interactions
Irradiated foods are not expected to interact with
any other foods, medicines, or products.Complications
There are no complications expected from con-
suming irradiated foods. Some concerned groups have
expressed fears that the long-term effects of eating
irradiated food are unknown. However, many differ-
ent scientific studies have examined the effects on both
animals and humans of consuming irradiated foods.
There has not been any evidence that irradiated foods
are harmful in either the short or the long term. One
study even examined many generations of animals fed
irradiated foods and found no harmful effects. Irradi-
ating food is accepted as a safe practice and is
endorsed by many organizations including the World
Health Organization, the Centers for Disease Control,
the United States Food and Drug Administration, and
the American Medical Association.Parental concerns
Some parents may have concerns that the vitamin
and nutrient content of irradiated foods may be
reduced compared to the content of the same foods
that have not been irradiated. For mostvitamins,min-
erals, and nutrients this is not the case. Studies haveshown that the levels of most vitamins in irradiated
foods are not significantly different from the levels in
foods that have not been irradiated. Some vitamins
however, such as thiamine (vitamin B 1 ), have been
found to be sensitive to irradiation. The extent to
which such vitamins are destroyed however, depends
greatly on type of food being irradiated. Thiamine was
found to be decreased by 50% in awatersolution that
was exposed to radiation, but only decreased by 5% in
a dried egg exposed to the same level of radiation.
Many vitamins, like thiamine, that are sensitive to
irradiation are as sensitive, or even more sensitive, to
heat, and are broken down at least as much by the
process of canning or heat treatments. Therefore,
although levels of some vitamins may be decreased in
irradiated foods compared to fresh foods, the levels of
these vitamins may be higher in irradiated foods than
in comparable canned or otherwise sterilized foods.Resources
BOOKS
Shannon, Joyce Brennfleck ed.Diet and Nutrition Source-
book. Detroit, MI: Omnigraphics, 2006.
Sommers, Christopher H. and Xuetong Fan.Food Irradia-
tion Research and Technology. Ames, Iowa: Blackwell
Pub., 2006.
ORGANIZATIONS
United States Department of Agriculture. 1400 Independ-
ence Avenue SW, Washington, DC 20250. Website:
<http://www.usda.gov>
United States Centers for Disease Control. 1600 Clifton
Road, Atlanta, GA 30333. Telephone: (800) 311-3435.
Website:<http://www.cdc.gov>
United States Food and Drug Administration. 5600 Fishers
Lane, Rockville, MD 20857-0001. Telephone: (888)
463-6332. Website:<http://www.fda.gov>
World Health Organization. Telephone: +41-22-791-2222.
Website:<http://www.who.int/en/>
OTHER
Organic Consumers Association. ‘‘Food Irradiation.’’ 2007.
<http://www.organicconsumers.org/irradlink.cfm>Tish Davidson, M.A.Irritable bowel syndrome
Definition
Irritable bowel syndrome (IBS) is an idiopathic
functional gastrointestinal disorder. More simply, the
bowel appears normal, but does not function correctly,Irritable bowel syndrome