Iowa State University
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News Service

News Service:

Annette Hacker, director,
(515) 294-3720

Office: (515) 294-4777

09-15-08

Contacts:

Dong Uk Ahn, Animal Science, 515-294-6595, duahn@iastate.edu

Dan Kuester, News Service, 515-294-0704, kuester@iastate.edu

New beef irradiation process improves appearance, odor of irradiated beef

AMES, Iowa --An Iowa State University researcher has found that adding certain natural products to beef before irradiating it allows the meat to maintain a healthy, red appearance and inhibits odors that can result from the process.

Dong Uk Ahn, animal science professor at Iowa State University, has worked for years to make irradiated beef more appealing.

"There are two major problems with irradiated meat," said Ahn. "One is color change. People buy meat on the basis of color. If they see that purple-red and bright-red color, they feel that it's fresher. If the color is brown or gray, no one is going to buy that meat. The other problem is odor."

By adding an antioxidant and vitamin E -- both natural compounds found in living organisms -- to beef, Ahn was able to keep the meat's appealing color. Irradiating and storing the meat with those additives in oxygen-permeable bags or vinyl wraps allow irradiation odor to evaporate quickly while preventing color change and odor-causing lipid oxidation.

Irradiating meat is the process of passing meat through a high-intensity, non-radioactive electron beam to kill bacteria, such as e. coli, salmonella and listeria, that may cause the consumer to become ill.

Ahn's method involves mixing in an antioxidant (ascorbic acid), and vitamin E (tocopherol) to the ground beef before irradiating it to allow oxygen to bind to the meat to retain the color.

The color change and odor that comes from irradiating meat is due to the oxidation of lipids and pigments, and small changes in proteins in the meat. Ahn's process slows down oxidation and removes the unfamiliar odor from irradiated meat.

Ahn's research involves ground beef since that is the type of meat most likely to benefit from the treatment. Ahn found the best way to get his additive into the meat is by mixing his additives into the meat during or after grinding, but before the meat is pressed into patties.

Ahn says irradiating beef has safety advantages for consumers and no loss of food value.

"The process benefits those who need it most, people who may be susceptible to illness brought on by the bacteria -- children, the elderly and others. And the nutritional value of the meat is not affected," he said.

Meat treated with irradiation is approved by the Food and Drug Administration and available at grocery stores or through companies by mail order. Currently, irradiated meat is mostly sold frozen. So, the rich, red color is less important to consumers than if they were buying fresh meat.

Currently, Ahn's research cannot be used on meat available to consumers. Irradiation is considered an additive by the FDA. Meat cannot have more than one additive by regulation. Ahn is hoping the FDA changes irradiation's classification from an additive to a treatment, or approves the use of irradiation in processed meat, a petition that has been pending since 1999.

"Once that hurdle is gone, there will be a lot of people who will be interested in this technology and bringing it to the marketplace." Ahn said

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Quick look

An ISU researcher has found that adding certain natural products to beef before irradiating it allows the meat to maintain a healthy, red appearance and inhibits off-odors.

Quote

The process benefits those who need it most, people who may be susceptible to illness brought on by the bacteria -- children, the elderly and others. And the nutritional value of the meat is not affected.

Dong Uk Ahn