Mixed Picture | January 15, 2007 Issue - Vol. 85 Issue 3 | Chemical & Engineering News
Volume 85 Issue 3 | p. 42
Issue Date: January 15, 2007

Mixed Picture

Irradiation Has Benefits But May Hurt Flavor
Department: Government & Policy

Other than spices and seasonings, ground beef and poultry are the primary foods irradiated in the U.S. The process clearly reduces pathogen levels in the products, but there is evidence that the treatment may degrade the flavor.

Irradiation was approved for spices in 1983 and for insect control on fruits and vegetables in 1986, but it was not approved for use on poultry until 1992 and on red meat until 1997. All irradiated products sold in stores or delivered to homes must display a "radura" symbol and the words "treated with irradiation" or "treated by irradiation" on the label.

According to Department of Agriculture rules, irradiation can be used on meat and poultry only after the food has met all food safety regulations and been inspected and passed by USDA. The department points out that the application of radiation, steam pasteurization, or any other pathogen-reduction strategy "does not mean the department will abandon or lessen its strict sanitation requirements or zero tolerance for fecal-matter contamination."

Currently, in the U.S., all the frozen ground beef sold by the high-end distributors Omaha Steaks and Schwan Food Co. is irradiated. In addition, thousands of supermarkets, including those owned by Wegmans and Publix, offer fresh irradiated ground beef. Only about 15 million lb of irradiated ground beef is sold annually, less than 1% of the total, says Ronald F. Eustice, executive director of the Minnesota Beef Council.

Wegmans successfully launched sales of irradiated ground beef in 2002 after it provided cooked samples in all stores for several weeks to allow customers the opportunity to taste the product before purchasing.

In 2003, Consumer Reports magazine, published by Consumers Union, conducted the largest study to date of irradiated products offered in supermarkets, purchasing 500 packages of both standard and irradiated chicken tenders and ground beef in 60 cities. It found that the irradiated products had lower pathogen levels than conventional foods but still contained measurable levels. And in blind taste tests, "trained testers noted a slight but distinct off taste and smell like singed hair in most of the irradiated beef and chicken that was cooked and sampled," but "because the off tastes are usually subtle, some consumers may not notice," Consumer Reports noted.

The magazine concluded that there is no reason to buy irradiated meat or poultry if "you cook meat thoroughly." It said the way irradiation is being promoted gives consumers a false sense of security and may take the focus off preventing contamination in the first place.

Consumers Union is opposed to end-of-pipe solutions. "Unlike systems that look at every critical control point, end-of-pipe solutions foster carelessness early on in the growing and production process," Jean Halloran, director of the Consumer Policy Institute, a division of Consumers Union, explains. "Then, if the final step fails for any reason, you can have a very serious problem."

The flavor changes in meat resulting from irradiation are caused by oxidation of lipids, says Aubrey Mendonca, a food science researcher at Iowa State University. Irradiation turns some of the water in the meat into free radicals that oxidize lipids, creating off tastes, he explains. "But if you freeze the meat before it is irradiated, you don't get a lot of these chemical changes," he says. The best approach is to use good sanitation, freeze the meat, and then irradiate it with the lowest effective dose, he observes.

Robert V. Tauxe, a medical officer at the Centers for Disease Control & Prevention, estimates that irradiating half of all ground beef, pork, poultry, and processed meat would prevent 900,000 cases of food-borne illness and 350 deaths in the U.S. each year (Emerg. Infect. Dis. 2001, 7, 516).


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