EVALUATION OF CHANGES IN MICROBIAL POPULATIONS ON BEEF CARCASSES RESULTING FROM STEAM PASTEURIZATION

Summary The steam pasteurization process (SPS result in emergence of “new” microorganisms 400) developed by Frigoscandia Food Pro- and lead to new issues in meat safety. cess Systems (Bellevue, WA) was effective in Changes in microflora caused by a decontamreducing bacterial populations in both labora- ination or processing treatment must be tory and commercial settings. The objective evaluated to ensure that new problems are of steam pasteurization and other meat de- not being created. Conversely, certain decontamination measures is to extend product contamination treatments may select for shelf life and improve safety by inhibiting or microflora that improve shelf life and even inactivating pathogens, while at the same sensory quality. Each decontamination strattime maintaining acceptable meat quality egy should be evaluated individually to ascercharacteristics. The effects of steam pasteur- tain its effects on the resulting microbiologiization on beef carcass bacterial populations cal safety and quality of meat products. were evaluated at two large commercial beef processing facilities. A shelf-life study also This experiment examined the effects of was conducted to determine the microbial steam pasteurization on beef carcass profiles of vacuum packaged beef loins from microflora. Our goal was to identify the pasteurized and non-pasteurized carcasses. types of native microflora of beef carcasses Steam pasteurization greatly reduced total before and after steam pasteurization and to beef carcass bacterial populations and was observe any changes resulting from this most effective in reducing gram negative treatment, compared to nontreated carcasses. organisms, including potential enteric patho- The changes in microflora in vacuum-packgens of fecal origin. Thus, the relative per- aged beef subprimals over time caused by centage of gram positive microflora on beef steam pasteurization of carcasses also were carcass surfaces, especially Bacillus spp. and analyzed. Staphylococcusspp., increased.