Microbiological contamination in three large-scale pig slaughterhouses in Northern Italy

Abstract

The aim of this survey was to obtain data on microbiological contamination of pig carcasses and environments in three large-scale Italian slaughterhouses (identified as A-B-C) located in Northern Italy. Each slaughterhouse was visited six times. Five carcasses and three different sites of the slaughterhouse (before and during slaughter) were sampled on each sampling day. A single pooled caecal sample was taken on each sampling day. A total of 90 carcasses, 108 environmental samples and 18 caecal samples were collected. Samples from pig carcasses and slaughterhouse environment were analyzed for Total Viable Count (TVC), <em>Enterobacteriaceae</em> count (EBC) and <em>Salmonella</em>. The caecal contents were examined for Salmonella. Carcasses from slaughterhouse A presented the greatest TVC and EBC mean log value, whereas environmental samples collected during slaughter activities from slaughterhouse C showed the greatest TVC and EBC mean log value. As far as the environmental samples collected before slaughter activities are concerned, an average up to 6 log10 CFU/cm2 TVC in two slaughter plants (A and C) and 5 log10 CFU/cm2 TVC in one slaughter plant (B) was detected. <em>Salmonella</em> was recovered in two slaughterhouses (A and B). Four different <em>Salmonella</em> serotypes were detected in the positive samples (11). Within serotype <em>S. Rissen</em> and <em>S. Typhimurium</em> monophasic-variant isolates, two PFGE patterns were identified. The findings in this survey suggest that carcass contamination is influenced by the slaughterhouse plant and this could be a result of differences in line speed. The results of environmental sampling have not shown an association with the slaughterhouse plant.