Prevalence of Salmonellae, Listeriae, and Yersiniae in the slaughterhouse environment and on work surfaces, equipment, and workers

In 1995 and 1996 a nine-month study was carried out in 11 pig abattoirs located in the Molise region (Italy) to evaluate the degree of contamination of the slaughterhouse environment, work surfaces, equipment, and personnel by Salmonella spp., Listeria spp., and Yersinia spp. A total of 219 samples were taken over three replications including slaughtering floor and wall, hooks, worktables, chopping blocks, knives, cleavers, dehairing devices, hands of personnel, clothing, hand-wash basins, and cold room handles, floor, wall, and hooks. Overall, six abattoirs (54.5%) had one or more positive sites, while only 14 of the 219 sites (6.4%) tested were positive for any of considered microorganisms. Salmonella spp. were isolated from 1 of 9 cleavers (11.1%), 1 of 16 worktables (6.25%), and 1 of 18 slaughtering floors (5.6%). Yersinia enterocolitica was found on 3 slaughtering floors (16.7%) and on 2 worktables (12.5%). Yersinia kristensenii was detected on 2 slaughtering floor swabs (11.1%). Listeria monocytogenes was isolated from 2 of 20 cold room floor swabs (13.3%) and from 1 of 14 hand-wash basins (7.1%). Other species of Listeria were detected on slaughtering wall and floor swabs and on chopping blocks. Our study indicates that slaughtering floors, cold room floors, and worktables are important sites in abattoirs that may possibly harbor pathogens like Salmonella spp., Yersinia enterocolitica, and Listeria monocytogenes, and that cleaning and sanitizing of the slaughterhouse environment and equipment need a greater emphasis.