Despite Assurances of Safety, Public Is Cold Toward Irradiation
More than 100 years have passed since heat-pasteurized milk was first introduced to the public, and few people today would argue against its benefits. The situation was very different, however, when the idea of sterilizing milk by heating it was first proposed. Critics questioned the need for pasteurization and expressed concerns about its safety.
A similar situation is now brewing over the irradiation of foods, a procedure designed to destroy potentially harmful organisms and improve the safety of the food supply. With this process, high-energy, invisible light waves are passed through food to kill bacteria and other dangerous organisms or to prevent them from reproducing. Since the high-energy waves affect only cells that are alive and growing (like bacteria), the food itself--which is “dead”--remains essentially undisturbed.
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The health benefits of irradiation are most obvious for raw food products, such as poultry and meat, that are often contaminated with bacteria known to cause disease. Poultry, for example, often harbors salmonella and campylobacter; ground beef may harbor E. coli O157:H7. Irradiation also offers an extra margin of safety for raw fruits and vegetables that can acquire dangerous organisms from the soil or from post-harvest handling.
Irradiation may reduce the need for other types of pest controls such as pesticides and fumigants, lowering the amount of chemical residues on and in these foods. In certain fruits and vegetables, irradiation inhibits sprouting and delays ripening. This reduces spoilage and extends shelf-life (for example, irradiated strawberries remain unspoiled for up to three weeks, compared with three to five days for untreated berries).
In spite of these benefits, there is significant opposition to irradiation, much of it based on fears that irradiation will leave food “radioactive” and, therefore, potentially dangerous. This concern is unwarranted. Scientific studies prove that irradiation leaves no signs of radioactivity in food. Although the gamma rays, X-rays or electron beams used to treat food are created by radioactive sources, the food never comes into direct contact with the radiation source.
Some chemical changes do occur during irradiation, but these changes are similar to the ones that occur with other food preservation methods, such as cooking and canning. The chemical byproducts of irradiation have been closely studied and found to be safe.
Irradiation does not change the way most food appears or tastes, nor does it significantly compromise the nutritional quality. Proteins, fats and carbohydrates are particularly resistant to irradiation; vitamins, however, are more sensitive to its effects, and some vitamin loss can occur. Such losses are typically quite small, however, and most experts do not think they could result in vitamin deficiency or nutritional problems.
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Irradiation can already be legally used on a wide variety of foods. The Food and Drug Administration has approved it for fresh and frozen poultry and meat, fruits and vegetables, and spices and seasonings. So consumers can readily identify them, irradiated foods must carry the radura logo (the international symbol for irradiation) along with one of the following two statements: “treated with radiation” or “treated by irradiation.” A brief statement describing the reason for irradiation may also be included (for example: to destroy harmful bacteria).
You are unlikely, however, to see the radura logo on many foods in your local grocery store. Despite widespread acceptance of irradiation by public health experts and respected health organizations (including the American Medical Assn., the American Dietetic Assn., the Centers for Disease Control and Prevention, and the World Health Organization), store owners are reluctant to stock these foods because they’re afraid that consumers won’t buy them.
In addition to overcoming concerns about radioactivity and quality, consumers must be willing to pay slightly more for products that have been irradiated. Industry experts estimate the price difference to be about 2 to 3 cents a pound for fruits and vegetables and 3 to 5 cents a pound for meat and poultry products.
If you decide to buy irradiated products, safe handling practices cannot be abandoned. Irradiated foods must be stored, handled and cooked in the same way as other foods. Even though the approved levels of irradiation will significantly reduce the number of organisms in a food, it does not destroy all of them, so irradiated food should not be considered sterile. The organisms that remain can begin to grow and multiply if the food is mishandled, and irradiated food can become contaminated after it is treated.
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Dr. Jonathan Fielding is the director of public health and the health officer for the Los Angeles County Department of Health Services. Dr. Valerie Ulene is a board-certified specialist in preventive medicine practicing in Los Angeles. They can be reached by e-mail at ourhealth@dhs.co.la.ca.us. Their column appears the second and fourth Mondays of the month.
