Effects of slaughterhouse personnel hygiene on the microbiological quality of small animal carcasses

Hygiene rules must be followed in order to reduce carcass contamination on slaughterhouse cutting line. This study was conducted to investigate how much change in the microbiological quality of small animal carcasses is obtained if the staff who work in slaughter line meet some hygiene rules. The study was carried out in two stages at two different slaughterhouses (A and B). In the first stage, each slaughterhouse was visited in a total three times, once per week, and the samples were taken from staff's hands/gloves/knives and pre-chill carcasses and then analyzed for total mesophilic aerobic bacteria (TMAB), Enterobacteriaceae and Salmonella spp. Thus, the general hygiene situation of the carcasses and the staffs in the slaughter line was revealed during the first stage of the study. In the second stage, the same slaughterhouses were visited three times as in the first stage, and during these visits the staffs were allowed to wear latex gloves and hair net, wash their gloved hands, disinfect their blades (by dipping into ≥82ºC hot water at least 5 sec) before they start to remove the skin of the randomly selected carcasses in slaughter line. After finishing the skinning procedure, the carcass samples were taken. The samples taken from staff's gloves and knives were analyzed as in the first stage in order to assess the effectiveness of hand washing and knife disinfecting procedures. In the first stage, TMAB and Enterobacteriaceae numbers of the carcasses in the slaughterhouse A were detected as 3.68 and 0.90 log10 CFU/cm2 while those numbers decreased to 3.60 and 0.41 log10 CFU/cm2 in the second stage of the study (after hygiene practices), respectively. TMAB and Enterobacteriaceae numbers of the carcasses in the slaughterhouse B were 3.88 and 1.77 log10 CFU/cm2 while those numbers decreased to 3.20 and 0.77 log10 CFU/cm2 in the second stage of the study, respectively (P<0.05). The carcasses in the slaughterhouse A were detected as Salmonella spp. negative in both the first and the second stage of the study. As for slaughterhouse B, four carcasses were Salmonella spp. positive in the first stage while none of the carcasses was Salmonella spp. positive in the second stage. In both slaughterhouse A and B, the average numbers of TMAB and Enterobacteriaceae on the staff hands and knives significantly reduced after hygiene practices (in the second stage) (P<0.05). The staff hands and knives in the slaughterhouse A were detected as Salmonella spp. negative in both the first and the second stage. As for slaughterhouse B, four staffs' hands and two knives were Salmonella spp. positive in the first stage while only one knife was detected as Salmonella spp. positive in the second stage. Consequently, it was detected that handwashing process and dipping knives into hot water (≥82oC, at least 5 sec) in slaughterhouse significantly reduced the microbial load of the contamination sources such as hand and knife, and these reductions provided the decrease in the numbers of TMAB by 0.08-0.68 and in the numbers of Enterobacteriaceae by 0.49-1.0 log10 CFU/cm2, respectively, on the small animal carcasses. However, it can be said that the reductions in the numbers of microorganisms on hands, knives and carcasses may increase depending on the skill and care of the staff and the design of the slaughter line.