Process mapping the prevalence of Salmonella contamination on pork carcass from slaughter to chilling: a systematic review approach.

A systematic review was conducted to identify and summarize primary research studies that describe the prevalence of Salmonella spp. in pork from slaughter to cooler in the member states of the European Union (EU), Australia, Canada, Hong Kong, Japan, Korea, Mexico, New Zealand, Taiwan, and United States (i.e., a process map). Relevant studies documented Salmonella spp. prevalence at more than one processing point using the same cohort of pigs or the same production line for the post-cooler component. Literature searches retrieved 6811 citations. Sixteen publications, describing 44 studies, evaluated the presence of Salmonella on pork carcasses. The carcass sampling points evaluated were as follows: stun, bleed, kill, scald, dehair, singe, polish, bung removal, evisceration, split, stamp, final wash, immediately after chill, and 18-48 h after chilling. Seventy-eight comparisons of Salmonella spp. prevalence between points along the processing line were reported. The median prevalence of Salmonella spp.-positive carcasses evaluated in the cooler was 0%. The median prevalence of Salmonella spp. after bleeding was 32%. Fifty-nine of the 78 point-to-point comparisons were associated with either no change or a decrease in Salmonella prevalence as the carcass moved closer to the cooler. Nineteen point-to-point changes showed an increase in Salmonella prevalence as the carcass moved toward the cooler; of these, six reported a greater than 10% increase in Salmonella prevalence. The majority of increases were associated with post-evisceration and splitting. These findings suggest that the processing procedures in place generally result in decreased prevalence of Salmonella spp. as the carcasses move toward the cooler.