Volume 44 Number 1 Spring 1997

IRRADIATION EXTENDS GROUND BEEF SHELFLIFE SIX WEEKS

U.S. Department of Agriculture officials are considering a petition to allow the irradiation of ground beef to improve its safety and shelf life. In preparation for this development, AAES food scientists are examining the effects of various levels of radiation on shelf life, bacterial content, sensory properties, and nutritional quality of ground beef.

Researchers are testing low doses of gamma radiation ranging from 1-7 kilograys (kGy); 1 kGyequals 100,000 rads. Preliminary results show that ground beef treated with 5-7 kGy was safe for consumption and of good quality up to six weeks in refrigeration. However, meat treated with 7 kGy developed an “off-odor” and strong aftertaste after six weeks of freezer storage. In the control treatment, untreated, refrigerated ground beef was inedible within a week.

Another interesting finding is that low doses of radiation (1-3 kGy) appear to merely injure E. Coli and bacteria associated with spoilage. Initial counts indicated no bacteria survived, regardless of dose level. But the bacteria recovered in low-dose treatments, whereas doses of 5-7 kGy killed all bacteria. Results from the vitamin content study are not yet analyzed.

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