Microbial populations on animal hides and beef carcasses at different stages of slaughter in plants employing multiple-sequential interventions for decontamination

Multiple-sequential interventions were applied commercially to reduce beef carcass contamination in eight packing plants. The study evaluated microbia l populations on animal hides and changes in carcass microbial populations at various stages in the slaughtering process. Sponge swab samples yielded mean (log CFU/100 cm(2)) total plate counts (TPC), total coliform counts (T CC), and Escherichia coli counts (ECC) on the exterior hide in the ranges o f 8,2 to 12.5, 6.0 to 7.9, and 5.5 to 7.5, respectively, while correspondin g contamination levels on carcass surfaces, after hide removal but before a pplication of any decontamination intervention, were in the ranges of 6.1 t o 9.1, 3.0 to 6.0, and 2.6 to 5.3, respectively. Following the slaughtering process and application of multiple-sequential decontamination interventio ns that included steam vacuuming, pre-evisceration carcass washing, pre-evi sceration organic acid solution rinsing, hot water carcass washing, postevi sceration final carcass washing, and postevisceration organic acid solution rinsing, mean TPC, TCC, and ECC on carcass surfaces were 3.8 to 7.1, 1.5 t o 3.7, and 1.0 to 3.0, respectively, while corresponding populations follow ing a 24 to 36 h chilling period were 2.3 to 5.3, 0.9 to 1.3, and 0.9, resp ectively. The results support the concept of using sequential decontaminati on processes in beef packing plants as a means of improving the microbiolog ical quality of beef carcasses.