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E. A. MURANO, Center for Food Safety, Texas A&M University, Department of Animal Science, Food Science Section, 310 Kleberg, College Station, TX 77843-2471

The application of ionizing radiation for decontamination of foods has been studied for more than four decades, not only in the U.S. but also in Europe and other parts of the world. The principle by which it improves food safety is by damaging the DNA molecule of microorganisms contaminating the product, effectively impeding their ability to carry out cell division and other important functions.

Research has shown that the irradiation doses approved for use by FDA on poultry and red meats will decrease the number of bacterial contaminants in these products by about 6 log cycles. The result is that pathogenic bacteria of public health significance, such as Listeria monocytogenes, Escherichia coli O157:H7, Salmonella, and Campylobacter, are virtually eliminated from these foods.

In addition to enhanced safety, ionizing radiation extends the shelf life significantly, with irradiated ground beef lasting up to 30 days in refrigerated storage, compared to 5 days for controls.

Research has shown that exposure of microorganisms to ionizing radiation in a commercial application will not result in development of microbial resistance to this treatment. In fact, any cell that survives does so in a weakened and fragile state, not able to survive subsequent storage.

When irradiation is used in conjunction with other intervention strategies such as heat or organic sanitizers, it can exert a synergistic effect, lowering the number of survivors further than if only one treatment is applied. Food irradiation is being considered an important tool in ensuring the safety of fresh meats, because of its effectiveness in eliminating pathogens while not affecting product quality. Given that the process itself is easy to control and monitor, irradiation falls within the definition of a "critical control point" within the HACCP system.