Decontamination of pork carcasses during scalding and the prevention of Salmonella cross-contamination

Aims: The objective of this study was to establish critical temperature limits to prevent cross-contamination of pork carcasses during scalding. Methods and Results: Mixtures of antibiotic-resistant mutants of Salmonella species were heat treated at 50, 55 and 60degreesC in samples of commercial scald tank water. Surviving cell numbers were estimated by plating treated suspensions on (i) tryptone soya agar (TSA) and (ii) on TSA, overlaid with brilliant green agar plus nalidixic acid and streptomycin sulphate and used to estimate D -values for the treated mixed cell suspensions. Conclusions: A time-temperature combination of 1.4 min at 60degreesC is required to achieve a 1 log reduction in Salmonella in scald tank water. The predicted equivalent at 65degreesC is 0.18 min. Significance and Impact of the Study: This study provides data and a model to enable pork processors to identify and apply processing parameters to limit the risks of transfer of Salmonella between pig carcasses during commercial scalding operations.