Purpose: The aim of this research was to assess the presence and map the distribution of Salmonella, ESBL/AmpC-producing E. coli and hygiene indicator bacteria on pig carcasses.
Methods: Seven Belgian pig slaughterhouses were visited twice to collect carcass swab samples after evisceration and trimming. During each visit, 9 carcass areas from 5 randomly selected carcasses were swabbed using cellulose sponges: foreleg, head, pelvic duct, sternum, belly, throat, distal part of the foreleg, ham and loin. All samples were analyzed using direct plating to quantify E. coli, Enterobacteriaceae and the total aerobic count. Furthermore, swab samples were analyzed for the presence of ESBL/AmpC-producing E. coli and Salmonella.
Results: Overall, the average total aerobic count varied between 3.1 (loin and pelvic duct) and 4.5 log10 CFU/cm2 (distal part of the foreleg) while median numbers for Enterobacteriaceae and E. coli ranged from values under the detection limit (ham respectively loin, foreleg and ham) up to 1.65 log10 CFU/cm2 respectively 1.18 log10 CFU/cm2 (both distal part of the foreleg). Salmonella was recovered from 4% (foreleg and ham) to 33% (distal part of the foreleg) of the samples. ESBL/AmpC-producing E. coli were found in none of the loin swabs and up to 20% of the head swabs. Respectively 53% and 41% of all carcasses were contaminated with Salmonella and ESBL/AmpC-producing E. coli, varying between slaughterhouses from none to all carcasses contaminated.
Significance: The large variations observed between slaughterhouses and carcass areas indicate the need for risk categorization of slaughterhouses, carcasses and pork cuts along the production chain.