Volatile sulfur compounds help generate off-odors in some irradiated products.

Advances in analytical techniques and instrumentation and mechanistic studies have led to a better understanding of the formation and mode of action of sulfur compounds and their impact on the flavor and off-flavor characteristics of foods. Irradiation has turned out to be a very effective way to inactivate pathogens in raw and ready-to-eat cooked meats. However, meat may develop an unpleasant odor when it is irradiated. Scientists at Iowa State University undertook a study to investigate how volatile sulfur compounds in precooked ready-to-eat (RTE) turkey breast react to doses of radiation and subsequent storage.

The investigators exposed precooked turkey breast to 0, 1, 2, 3, 4 and 5 kGy of gamma radiation and then stored the product for 14 days at 5 C. Volatile sulfur compounds were extracted using solid-phase microextraction. This was followed by applying gas chromatographic separation and pulsed-flame photometric detection.

The scientists identified seven volatile sulfur compounds. Irradiation dramatically increased concentrations of all but one volatile sulfur compound. However, concentrations of all volatile sulfur compounds decreased in both irradiated and nonirradiated samples when they were stored. Carbon disulfide was the only volatile sulfur compound whose levels were reduced by using irradiation. Concentrations of all volatile sulfur compounds decreased in both irradiated and non-irradiated samples stored at 5 C.

It's apparent from this research that that volatile sulfur compounds are involved in the generation of the off-odors.

Further information. Joseph Sebranek, 215 Meat Lab, Iowa State University, Ames, IA 50011; phone: [phone]; fax: [phone]; email: [e-mail].