CONTAMINATION OF THE LAIRAGE OF A PORK ABATTOIR WITH SALMONELLA SPECIES

Abstract The objectives of this study were to determine the prevalence of Salmonella spp. in the lairage of a pork abattoir on different days of the week and to investigate the effect of daily wash-ing routines and disinfection procedures on contamination levels with Salmonella spp. In total, 359 swabs were collected from lairage pen floors at three time points during the course of two slaughter days. All samples were analysed quantitatively. On day 1 (Monday), following cleaning and disinfection, 6 % of samples were positive for Salmonella spp. On day 2 (Thursday), lairage pens were subjected to cold water washing in between batches of pigs; 44 % of samples were positive for Salmonella spp. The number of positive samples isolated increased significantly over the course of the slaughter week (P <0.001). Quantitative analysis revealed that the numbers of salmonellae rose from <0.46 organisms/100cm2 to levels of approximately 4 organisms/100cm2 over the course of the week. Introduction Studies have shown that the lairage environment in pork plants can be highly con-taminated with Salmonella enterica (Rostagno et al., 2003), (Swanenburg et al., 2001a). In addi-tion it has been demonstrated that pigs can become rapidly infected with S. Typhimurium, when exposed to a contaminated environment (Hurd et al., 2001). Therefore the lairage may represent