Following the 2008 Canadian listeriosis outbreak associated with ready-to-eat (RTE) meat products, regulations on the presence of Listeria monocytogenes in RTE food production facilities were modified by Health Canada, confirming the need to control this pathogen, not only in the final product but also in the plant environment. Information on the occurrence of this microorganism during the early steps of production, such as the slaughtering process and in the cutting area, is scarce in Canada. In this study, we sampled different production steps in a slaughtering and cutting plant in the province of Quebec over a 2-year period. The lairage pens, representative areas of the slaughter line, and cutting zones were targeted after their respective cleaning procedures. A total of 874 samples were analyzed for the presence of L. monocytogenes. Characterization was done by first genoserogrouping the isolates using multiplex PCR and then using a pulsed-field gel electrophoresis approach. L. monocytogenes was detected throughout all production stages. The 108 positive samples found were analyzed further, and we established that there were 4 different serogroups, with serogroup IIb being the most prevalent. The results of pulsed-field gel electrophoresis analysis showed a significant decrease in the diversity of strains from the first areas of the plant to the cutting room (10 pulsotypes in 13 positive samples in lairage and 9 in 86 positive samples in cutting) and also showed the overrepresentation of a single predominant strain in the cutting room environment (type 1, representing 96.1% of the isolates). Biofilm formation analysis of the strains cannot exclusively explain the transitions we observed. A strong genotypic similarity between strains isolated in the early production areas and some strains in the cutting room was shown. These results support the need for better surveillance of L. monocytogenes prior to RTE food production in order to design control strategies that are better adapted from a public health perspective.

Salmonella is a foodborne pathogen commonly associated with poultry products. The aims of this work were to 1) estimate the impact of critical steps of the slaughter process on Salmonella detection from broiler chicken carcasses in two commercial poultry slaughter plants in Quebec, Canada, 2) investigate the presence of the pathogen in the slaughter plant environment, 3) describe, using a high resolution melting (HRM) approach, the HRM Salmonella profiles and serotypes present on carcasses and in the slaughter plant environment and 4) evaluate if the HRM flock status after chilling could be predicted by the flock status at previous steps of the slaughter process, or by the status of previous flocks, or by the status of the processing environment, for a same HRM profile. Eight visits were conducted in each slaughter plant over a 6-month period. A total of 379 carcass rinsates from 79 flocks were collected at 5 critical steps of the slaughter process. Environmental samples were also collected from seven critical sites in each slaughter plant. The bleeding step was the most contaminated with >92% of positive carcasses. A decrease of the contamination along the slaughtering process was noted, with carcasses sampled after dry-air chilling showing ≤2.5% Salmonella prevalence. The most frequently isolated serotypes were S. Heidelberg, S. Kentucky and S. Schwarzengrund. The detection of the S. Heidelberg 1-1-1 HRM profile on carcasses after chilling was significantly associated with its detection at previous steps of the slaughter process and in previously slaughtered flocks during a same sampling day. Results highlight the importance of the chilling step in the control of Salmonella on broiler chicken carcasses and the need to further describe and compare the competitive advantage of Salmonella serotypes to survive processing. The current study also illustrates the usefulness of HRM typing in investigating Salmonella contamination along the slaughter process.

Clostridium perfringens ranks among the three most frequent bacterial pathogens causing human foodborne diseases in Canada, and poultry meat products are identified as a source of infection for humans. The objective of the current study was to estimate the proportion of broiler chicken flocks, carcasses and various environmental samples from critical locations of the slaughter plant positive for the presence of C. perfringens enterotoxin encoding gene ( cpe ). From the 16 visits conducted, 25% of the 79 flocks sampled, 10% of the 379 carcasses sampled and 5% of the 217 environmental samples collected were found positive for cpe. The proportion of cpe -positive carcasses was statistically different between surveyed plants, with 17.0% for one abattoir and 2.2% for the other. For the most contaminated plant, cpe -positive carcasses were identified at each step of the processing line, with prevalence varying between 10.0% and 25.0%, whereas this prevalence varied between 0% and 25.0% for the environmental surfaces sampled. Based on the results obtained, enterotoxigenic C. perfringens strains could potentially represent a risk for the consumer.

Listeria monocytogenes is the etiological agent of listeriosis, a major foodborne disease and an important public health concern. Contamination of meat with L. monocytogenes occurs frequently at the slaughterhouse. Our aims were; 1) to investigate the distribution of L. monocytogenes in the processing areas of four swine slaughterhouses; 2) to describe the diversity of L. monocytogenes strains by pulsed-field gel electrophoresis; 3) to identify persistent L. monocytogenes strains and describe their distribution; 4) to investigate the associations between persistence of strains and their following characteristics: detection in food isolates, detection in human clinical isolates, and the presence of benzalkonium chloride (BAC) resistance genes. Various operation areas within the four swine slaughterhouses were sampled on four occasions. A total of 2496 samples were analyzed, and L. monocytogenes was successfully isolated from 243 samples. The proportion of positive samples ranged from 32 to 58% in each slaughterhouse and from 24 to 68% in each operation area. Fifty-eight different pulsotypes were identified and eight pulsotypes, present in samples collected during 4 visits, were considered persistent. The persistent pulsotypes were significantly more likely to be detected in food (P < 0.01, exact χ 2) and human clinical cases (P < 0.01, exact χ 2), respectively. Among pulsotypes harboring the BAC bcrABC resistance cassette or the emrE multidrug transporter gene, 42.8% were persistent compared to 4.5% for pulsotypes without these resistance genes (P < 0.01, exact χ 2). Our study highlights the importance of persistent L. monocytogenes strains in the environmental contamination of slaughterhouses, which may lead to repeated contamination of meat products. It also

Carriers of Salmonella in finishing pigs are believed to be a main source of carcass and pork contamination at the slaughterhouse and during meat processing. To better control the presence of Salmonella at the farm and slaughter, it is important to adequately identify on-farm risk factors associated with presence of these bacteria in animals. Thus a study was performed to identify the risk factors associated with the presence of Salmonella in live animals and on carcasses from 312 herds in Canada. A questionnaire was designed to gather information on several factors present on the farm and was completed by the producers. Results from the multivariate logistic regression analyses of all the factors indicated a significant effect of the type of feed grind (p = 0.0001), pen size (p=0.006), truck load capacity (p=0.008), clinical signs of salmonellosis (p=0.03) and a marginal effect of number of sources of finishing pigs (p = 0.098). Carcasses from highly contaminated herds were more likely of being Salmonella positive. Limiting the presence of Salmonella in the meat should therefore begin by reducing the number of herds highly contaminated by Salmonella.