Détection et caractérisation génétique de Listeria monocytogenes dans une usine 
d’abattage/découpe de porcs au Québec
Listeria monocytogenes (L. monocytogenes) is a major public health concern as it was illustrated by the 2008 episodes in cheese and ready-to-eat meat. In Canada, there is currently no surveillance policy of this microorganism in the production steps preceding transformation of ready-to-eat products. The presence and the circulation of this microorganism in these environments is not well documented either. To describe these parameters, we sampled a Quebec slaughtering and cutting plant in the lairage pens and on representative areas of the slaughter process and cutting rooms after washing and disinfection, during a two-year period. A total of 874 samples were collected. Listeria detection followed the MFHPB-30 Health Canada standard method, serotype confirmation was obtained by PCR and isolates were characterized by Apa1 and Asc1 RFLP-PFGE genotyping. We reported detection of Listeria monocytogenes in all stages of production. Among the positive samples, 4 different serovars (mainly 1/2b) emerged. PFGE patterns showed presence of a variety of different genotypes in the lairage and slaughtering areas of the plant and the presence of a major type in the environment of the cutting room (type 1 representing 96.1% of the strains at this step). Furthermore, strains found at the lairage pens were related to strains in the cutting room. These results suggest that Listeria monocytogenes can enter the plant with the animals, contaminate further production steps and that some strains can be selected and their growth promoted in the environment. Hence, becoming predominant, persistant and a food safety issue.
Listeria monocytogenes PFGE Pork Slaughterhouse Environment Cutting room Lairage pens