According to a report just released by the Council for Agricultural Science and Technology (CAST), a consortium of 30 scientific and professional societies, foodborne bacteria cause as many as 9,000 deaths in the United States annually; yet scientifically proven safe, low doses of pasteurizing radiation can kill over 99% percent of most foodborne bacteria.
The report was written and reviewed by more than a dozen scientists from public and private agencies, academia, and industry, who concluded that radiation pasteurization safely controls foodborne pathogens on beef, pork, lamb, and seafood. It therefore can protect consumers from such potentially devastating diseases as salmonellosis, hemorrhagic diarrhea caused by Escherichia coli O157:H7, and certain types of gastroenteritis.
In fact, “the safety and effectiveness of irradiation pasteurization is attested to by a broad spectrum of authorities,” adds report cochair Dr. Donald W. Thayer of the Food Safety Research Unit of the Eastern Regional Research Center, U.S. Department of Agriculture Agricultural Research Service. In addition to the USDA, the U.S. Food and Drug Administration, the World Health Organization, the Codex Alimentarius Commission, the American Medical Association, the American Dietetic Association, the Institute of Food Technologists, and the health authorities of approximately 40 countries all endorse the practice.
The Problem of Foodborne Illness
Although largely preventable, foodborne illness remains a serious problem in the United States. Foodborne diseases caused by pathogenic bacteria may cause as many as 9,000 deaths each year and 6.5 million to 33 million cases of diarrheal disease. The annual economic losses associated with foodborne disease in the United States may be as large as $5 billion or $6 billion.
Thayer states that “recent outbreaks of disease caused by Escherichia coli O157:H7 in hamburger, particularly in the Northwest, where there were more than 700 cases and four deaths from a single outbreak, point to how serious the foodborne disease problem is. That strain of E. coli alone still causes some 8,000 to 20,000 cases of disease every year in the U.S.”
Safety, Healthfulness Proven
“What consumers may not understand is that while food is being irradiated, it’s never in contact with radioactive material,” says report cochair Dr. Edward Josephson of the Food Science and Nutrition Research Center of the University of Rhode Island. “And, contrary to what some may have been told, the gamma rays, x-rays, or electrons used to treat it can’t make it radioactive.”
It is the rapidly growing cells of insects or spoilage and pathogenic bacteria that are killed when food is irradiated. There is little effect on the food itself because its cells are not multiplying.
Longterm animal studies have demonstrated that irradiated foods are completely safe and that their nutritional value remains essentially unaltered.
Josephson also points to the “widespread misconception that U.S. consumers will not accept irradiated food. But attitude studies and market tests show the contrary. For instance, when consumers are provided factual information about products and a choice between irradiated and nonirradiated food, they’ll pay premiums for irradiated poultry and pork.”
To control for the disease trichinosis, both the FDA and the USDA’s Food Safety and Inspection Service approved in 1986 the irradiation of fresh or previously frozen pork. Regulations permitting poultry irradiation to control foodborne pathogens were approved by the FDA in 1990 and by the FSIS in 1992.
Irradiation has been demonstrated to control Salmonella, Shigella, Staphylococcus aureus, enteropathogenic Escherichia coli, Vibrio cholerae, V. parahaemo lyticus, V. vulnificus, and hepatitis A virus, all of which have been associated with fish and shellfish. Vibrio vulnificus in undercooked oysters, for instance, may cause gastroenteritis or septicemia, which has a mortality rate exceeding 50%.
Most spices are dried in the open air and become severely contaminated by air- and soilborne bacteria, fungi, and insects. Bacterial plate counts of one to 100 million per gram of spice are not unusual. Thayer explains that this has led to the practice of fumigating with methyl bromide to eliminate insects or with ethylene oxide to eliminate bacteria and mold. “Both substances are extremely toxic,” he says, “and methyl bromide can deplete the atmospheric ozone layer. But the U.S. Clean Air Act and the Montreal Protocol of the Vienna Convention require any substance considered ozone depleting to be withdrawn from production and use by 2001. Pasteurizing radiation is a much more environmentally benign solution.”
U.S. fruits such as strawberries and papaya, and vegetables also are being treated with ionizing radiation to eliminate insects and spoilage organisms and to prevent overripening and in the case of tubers and bulbs, sprouting. Irradiation of tomatoes not only extends their shelf life but also allows them to be harvested when fully ripe, improving flavor.
As much as 400,000 tons per year of imported wheat are irradiated with an electron beam to kill insects at the port of Odessa, Ukraine. This process was developed through U.S. Army/ARS research and approved for use in the United States in 1963. It has not been used here because of the availability of fumigants and physical methods for separating insects from grain.
It is unlikely that all meat and poultry products ever would be treated with ionizing radiation; rather, irradiated meat and poultry likely would be chosen by customers who desire or require a greater degree of food safety, and by food service establishments to protect children and others at high risk from foodborne pathogens.
Limits of Radiation Pasteurization
The potential for consumer infection by pathogens is decreased greatly and shelf life extended by radiation pasteurization of meat and poultry. This benefit can be achieved only in products that are packaged and of the highest quality before being irradiated.
Radiation pasteurized products are neither sterile nor shelf stable and must be properly refrigerated, cooked, and served. The practice serves as one of the processor’s last quality-control steps, assuring both the processor and the consumer of product safety.
Related Publications: Radiation Pasteurization of Food
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