Uses on the Farm

Nuclear Nutrition?

Most people are amazed to learn that nuclear energy plays an important role in ensuring that we have safe and healthy food. Radioisotopes help farmers control insect infestations and scientists develop fertilizers that promote better and healthier plant crops.

Irradiation to preserve food has been approved for use in the United States by the U.S. Department of Agriculture, and the technique is commonly used in many countries throughout the world. The International Atomic Energy Agency, under charter by the United Nations, has a number of coordinated programs to preserve foods that are important to developing nations. In a world that produces more than enough food for its inhabitants but where millions still starve, the preservation of food by irradiation may well be the key to a more efficient distribution of food.

Helping Plants Grow

The use of radioisotopes to control insects that destroy crops offers farmers an alternative to chemical pesticides.

In the procedure, thousands of male insect pests are raised in a laboratory and exposed to sterilizing doses of radiation by being placed near a powerful radioisotope such as cobalt-60. This renders the male insects infertile. The sterilized males are then released in an area where insect infestation is a problem. When these insects mate with the females in that area, the eggs produced by the female will not be fertilized and, therefore, will not hatch. Pest populations are then drastically reduced and, in some cases, completely eliminated.

Screwworm infestation in the Southeastern United States was eliminated by this technique in the middle 1950s. Sterilizing male insects essentially solved the Mediterranean fruit fly infestation in California in the middle 1970s. The successful control of mosquitoes and flies, such as the tsetse, melon, and horn, has also been demonstrated in various countries throughout the world.

Because chemical pesticides are not used, no harmful residues are left on crops. In addition, the approach does not kill beneficial insects.

Cutting Down on Fertilizers

Adding radioisotope tracers to chemicals in fertilizers enables scientists to study the nutritional needs of plants. Radiotracers allow us to determine the uptake of chemicals by the plants and the efficiency of fertilization. This knowledge helps agronomists to raise a better and greater variety of plants and to make more economic use of fertilizers, water, and land resources. Through such means, it has been estimated that the worldwide consumption of fertilizers could be cut in half.

In nature, some plant seeds grow into plants with traits that differ from the parent plant. Some of these new variations improve the plants, and others do not. Historically, people have selected plants with useful traits and cultivated the seeds. Desirable properties-including increased yields, improved resistance to disease, better adaptability, and earlier ripening-have sometimes been achieved by exposing seeds to radioisotopes. With radioisotopes, researchers are often able to achieve the desired traits faster than is possible using chemical agents or conventional methods of crossbreeding.

One example of an important plant change induced by radiation is the peppermint plant. The Mitcham variety was the only source of peppermint oil in the United States. When it fell victim to a wilt disease, soil fumigation and crossbreeding techniques yielded plants either still susceptible to the disease or plants with oils that had unsatisfactory flavors. Radiation techniques led to a disease-resistant variety of the plant with properly flavored peppermint oil.

Preserving Food without Chemicals

One of the most exciting applications of radiation from radioisotopes is the preservation of foods for extended periods of time. Irradiation makes chemical additives and refrigeration unnecessary. The technique also requires less energy than other food preservation methods.

The usefulness of food preservation by radiation is well illustrated by our manned space explorations. Astronauts took food sterilized by irradiation to the moon and on shuttle flights. Moreover, they preferred it to all other types of preserved food.

Back on Earth, preserving food by irradiation is under study by the U.S. Department of Agriculture; however, it has been slow to develop in the United States, probably because of the extensive availability of refrigeration and lack of economic incentives. The technique is having a greater impact abroad, however, particularly in developing nations where many people have not had enough food to eat, in part, because of food spoilage.

Food is irradiated by exposing it to gamma rays from radioisotopes. Cobalt-60 is the radioisotope in general use. The radiation process destroys bacteria, viruses, molds, and insects that cause spoilage and disease.

Exposing food to radiation does not make it become radioactive, and its nutritional value is not significantly changed. Irradiating food increases its shelf life, kills insects in grains and stored foods, inhibits the sprouting of vegetables such as potatoes and onions, delays the ripening of certain fruits, and, at the highest doses, completely sterilizes food.

Starting in 1963, the U.S. Food and Drug Administration (FDA) has established regulations over the years that approved the gamma radiation of wheat and wheat flour, white potatoes, various herbs, spices, natural flavorings, and vegetable seasonings. In 1985, the FDA approved the commercial irradiation of pork to destroy the parasite causing trichinosis. The FDA has proposed standards covering food irradiation practices and irradiated food-labeling requirements. Labels will identify such foods and conditions of treatment.

Gamma irradiation of food does not render it unsafe for consumption. A 1984 International Atomic Energy Agency bulletin states that more than 25 years of testing the wholesomeness of radiation-preserved food throughout the world showed no harmful effects from its consumption. In 1983, the government of Japan sponsored the Asian Regional Cooperative Project on Food Irradiation. Eleven countries participated in the program: Bangladesh, India, Indonesia, Japan, Republic of Korea, Malaysia, Pakistan, Philippines, Sri Lanka, Thailand, and Vietnam. Despite the lack of evidence of any ill effects, the FDA is continuing studies to ensure that all irradiated food is safe to eat.

Links for more information..
Centers for Disease Control and Prevention: Food Irradiation
U.S. Food and Drug Administration: Food Irradiation: A Safe Measure
Kids, Teens & Educators
Nuclear Technology's Numerous Uses