Packaging methods impact irradiated meats.

Although irradiated meat products haven't been marketed in the United States, researchers are examining the effects of irradiation on such qualities as aroma. At Iowa State University (Department of Animal Science, Ames, IA 50011), researchers looked at irradiation's effects on cooked pork sausage in different types of packaging.

They found that irradiating the cooked pork sausage in aerobic packaging may result in a loss of some meaty aroma. The resulting odor was described by sensory testing panel members as similar to the odor of wet wool or wet hair. The use of vacuum packaging, however, may protect against the development of off-odors. Investigators did not address whether the changes in aroma would be noticed by consumers, or whether the acceptability of the product would be affected.

Odors develop in cooked meats through lipid oxidation. Irradiation generates atoms that accelerate the oxidation process and the onset of odors described as similar to wet hair. Irradiation also creates volatiles responsible for off-odors. In this research, irradiated sausages produced more volatiles than nonirradiated sausages, except for those irradiated sausages stored for at least eight days. Investigators also have examined irradiation's impact on other raw and cooked meats. They found similar results for turkey and pork.

Cooked meat is more susceptible to oxidative change than raw meat. The cooking process destroys the structure of the muscle fibers, enabling air and oxidative molecules to interact and produce the odors. The levels of fatty acids used in cooked meats can produce different levels of odors from lipid oxidation. Processors might have a way to alter their techniques to minimize the effect on irradiation-induced odors. Future research will determine how to prevent undesirable qualities that might cause consumers to turn away from irradiated meat.

It appears that vacuum packaging might be preferred as a way to prevent off-odors. But then color becomes the next factor to consider. The use of vacuum packaging on irradiated cooked sausages causes the color to change to a more reddish and pinkish tone. Consumers often like to see a color other than brown in their raw meats, but in cooked meat the situation is different. In the cooked meat the scientists used, they did not add curing agents to make the product pink as in sausages or hams. The pinkish color might not be desirable to consumers. The next step would then be to educate consumers so they understand that a pink color doesn't mean that the cooked meat is bad. Further information. Dong Ahn; phone: [phone]; fax: [phone].