Evolution of pig carcass and slaughterhouse environment contamination by Salmonella

The aims of this study were to determine Salmonella prevalence of slaughtered pigs and effects of slaughtering process on pig carcass contamination by Salmonella, to serotype the strains isolated and to identify the routes of Salmonella contamination inside slaughterhouse. Pork carcasses and slaughterhouse environment were sampled at three steps of the slaughter process and at three separate times in the working day respectively. Salmonella isolates were recovered using VIDAS ICS, then serotyped and pulsotyped. Carcass contamination significantly decreased between bleeding and chilling but environmental contamination variation depended on the slaughterhouse. The most recovered serotypes were Salmonella Derby and Salmonella Typhimurium. Some strains were recovered from two slaughterhouses. The routes of contamination inside a slaughterhouse remain unclear since there are some predominant clones in France, but the level of environmental contamination may play a part. Regular cleaning-disinfecting is required to limit carcass cross-contamination from the environment.