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Food Safety: The Role of Irradiation Processing


Thomas Worley
Revised February 1996


KEYWORDS: Irradiation, Food safety, Consumer


Unfortunate episodes with disease and death linked to specific foods or food sources serve as vivid reminders that the safety and wholesomeness of our food can never be taken for granted. For example, when E. coli in under cooked hamburger was linked to the deaths of children or cyanide was detected on imported grapes; widespread media coverage raised public concern for food safety for a few weeks or months. Most food safety issues are long-run in nature, however, and do not receive media coverage on a continuing basis. The U.S. Food and Drug Administration and the Center for Disease Control estimate that as many as 33 million people, or 14 percent of the population become ill annually from microorganisms in food. In most of these cases, the health problem that results is a mere inconvenience, although it can be life threatening for others; 9,000 deaths annually are attributed to food borne causes. Only a very small proportion of even the fatal illnesses receive widespread news coverage.

America already has one of the safest, most abundant, and varied food supplies in the world. Current high levels of safety, though, should not permit any sense of complacency toward continued improvement in the safety and wholesomeness of food on anyone's part. Reduction and prevention of disease caused by food borne pathogens is a responsibility shared by all participants in our food system, from farm input suppliers to consumers. Consumers and commercial food preparers are still first and foremost in the prevention of illness caused by food since most illness related to food is the result of improper storage, handling, or cooking. Farmers, food processors, food handlers, and government have big stakes in improving their performance in delivery of the safest food possible to consumers in supermarkets or restaurants. Food processors and handlers take their role in food safety very seriously and are subject to strict compliance with regulations concerning their operations and procedures. These commercial interests of the food system are now considering a new technology of food preservation with potential to increase the safety of foods - irradiation processing.

In terms of end effect, irradiation is much like the pasteurization process for milk. Unlike milk pasteurization, though, which relies on heat to kill pathogens, the irradiation process involves exposing foods to low doses of ionizing radiation from x-rays, gamma rays, or electron beams to greatly reduce, although not necessarily eliminate bacteria and insects. Irradiation processing can be referred to as "cold sterilization" because it does not appreciably raise the temperature or cook foods, therefore, foods do not change in texture or flavor. Fresh fruits and vegetables maintain their freshness and nutrient content after being processed with radiation. Foods processed by irradiation do not have residues and do not become radioactive in the process.

The irradiation process is carried out in a specially built chamber at controlled rates and times specific to each food being treated. An irradiation facility for food processing does not resemble a nuclear reactor in any way. The facilities for food irradiation are similar to numerous facilities throughout the United States that use ionizing energy to sterilize medical instruments and supplies. Foods are processed by beaming low-level ionizing radiation at products moving on a conveyor or on pallets making it applicable to a wide array of solid foods in various stages of packaging and processing.

Food irradiation is not a recently developed technology, having been in existence since the 1950's. The process kills bacteria, insect pests, and their larva thereby reducing chances of contracting food born disease while at the same time increasing shelf life of the treated foods. Although the process is quite controversial, a substantial body of scientific evidence indicates that the process is safe and unharmful to foods so treated according to the U.S. Food and Drug Administration (FDA). The World Health Organization, the American Medical Association, and the International Atomic Energy Agency have all approved the safety of the process. Irradiation of various foods has been approved in 37 countries to date and is extensively used in some of these nations.

In the U.S. so far, the FDA has approved the use of irradiation to control sprouting in potatoes; to control insects and their larvae in wheat, wheat powder, fresh fruits and vegetables, spices and other aromatic seasonings; to kill Trichinae in pork and to kill Salmonella bacteria in poultry. Currently, the FDA is considering a proposal to approve irradiation of beef to control naturally occurring E. coli bacteria. The only U.S. commercial facility relying on irradiation processing of food as its principal business is located in Mulberry, Florida and has been in operation since 1992. Fresh produce including strawberries, tomatoes and onions as well as poultry are processed at the plant for distribution to Midwestern supermarkets.

Currently, most consumers know little about irradiation of foods and its potential to improve the safety of foods. A recent Gallup Poll conducted for the American Meat Institute revealed that although 74 percent of consumers had heard of food irradiation only 24 percent claimed to have any knowledge of the process. These results indicate the need for the public to be better informed about the irradiation process and the safety benefits it can provide. Only when consumers become knowledgeable of the risks and benefits of irradiation can the process become widely adopted to improve food safety.

Understandably, consumers are concerned about using something they associate with deadly force on their foods. These concerns are succinctly expressed in a consumer's letter to the Wall Street Journal in response to an editorial supportive of food irradiation. He stated in his letter that, "No, I don't wish to routinely buy strawberries that stay fresh for a month or chicken that doesn't spoil easily. - Bug Off!" This same consumer stated that his position was, "preference and not hysteria."

In order for consumers such as this to exercise their preference in the marketplace, foods treated with irradiation are required to be labeled as such. FDA regulations require that an international symbol for irradiation and the words, "Treated by Irradiation," be included on the labels. Labeling is a partial solution to the dilemma of a technology that has benefits but may not be recognized or embraced by all consumers. Clearly stating on a label that irradiation processes have been used, however, is only part of the needed information. Additional information will need to be supplied on the labels or on posters or shelf cards in supermarkets so that the safety benefits of irradiation processing can become understood and disseminated among consumers. Informed consumers will then be in position to judge the desirability of the foods processed with irradiation based on personal preference and experience, or those opinions of acquaintances whose views they trust.

Some consumers view irradiation as a move toward the opposite pole from their desire to return to natural or organic production methods. These consumers now have options at the marketplace. Organic standards and procedures are being developed for foods produced and processed differently than conventionally produced foods. The irradiation process can represent a movement away from chemical dependence and toward fewer residues in foods. Perhaps these sometimes conflicting goals can be partially met by offering consumers the choice of safer food resulting from irradiation processing.


Thomas Worley is a member of the Western Extension Marketing Committee and is an Extension Economist at Washington State University. 

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