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The Canadian Food Inspection Agency is developing an Establishment-based Risk Assessment (ERA) model for commercial and on-farm mills involved in the manufacture, storage, packaging, labeling, or distribution of livestock feed (ERA-Feed Mill model). This model will help inform the allocation of inspection resources on the basis of feed safety risk, including animal health and food safety risk. In a previous study, 34 risk factors, grouped into inherent, mitigation, and compliance clusters, along with assessment criteria were selected. The objective of this current study was to estimate the relative risk (RR) of the 203 assessment criteria on the basis of the impact on feed safety to design an ERA-Feed Mill model algorithm. Furthermore, the intent of this study was to assess the maximum increase or decrease of risk obtained when multiple criteria belonging to a same cluster were identified in a specific feed mill. To do so, a two-round face-to-face expert elicitation was conducted with 28 Canadian feed experts. Results showed no significant association between respondent profiles (years of experience and work sector) and estimated RR. Uniformity of answers between experts improved between rounds. Criteria having the highest increase in risk (median RR ≥ 4) included the presence of materials prohibited to be fed to ruminants in a facility that produces ruminant feed, the presence of multiple livestock species on-site, and historical noncompliances related to the inspection of the feed mill's process control and end-product control programs. Risk mitigation criteria having the highest impact on decreasing the risk were the implementation of feed safety certifications, the use of dedicated manufacturing lines (prohibited materials or medications), and having a hazard sampling plan in place for finished feed. The median RR assigned to each criterion and cluster will be used to build an algorithm of the Canadian Food Inspection Agency's ERA-Feed Mill model. HIGHLIGHTS

Salmonella is a foodborne pathogen commonly associated with poultry products. The aims of this work were to (i) 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; (ii) investigate the presence of Salmonella in the slaughter plant environment; (iii) describe, using a high-resolution melting (HRM) approach, the HRM Salmonella profiles and serotypes present on carcasses and in the slaughter plant environment; and (iv) evaluate whether the HRM flock status after chilling could be predicted by the flock status at previous steps of the slaughter process, the status of previous flocks, or the status of the processing environment, for the same HRM profile. Eight visits were conducted in each slaughter plant over a 6-month period. In total, 379 carcass rinsates from 79 flocks were collected at five 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% 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 Salmonella Heidelberg, Kentucky, and Schwarzengrund. The detection of the Salmonella 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 from other farms 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. HIGHLIGHTS

The Canadian Food Inspection Agency is developing an Establishment-based Risk Assessment model for Hatcheries to allocate inspection resources according to the food safety risk associated with each hatchery falling under its jurisdiction. In a previous study, 29 factors contributing to the food safety risk of hatcheries were identified and grouped into three clusters (inherent risk, risk mitigation, and compliance) and assessment criteria were defined. The objective of the current study was to estimate the relative risk (RR) of these criteria. Two rounds of expert elicitations were conducted to allow 13 Canadian experts to estimate the RR of each criterion (

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Agricultural practices such as manure applications could contribute to the spread of antibiotic resistance genes (ARGs) within the environment. Our objective was to assess the impact of certain fertilization methods (mineral or manure) and tillage practices (reduced or conventional) on the presence of ARGs and bacteria in soil and drainage water under wheat and grain corn crops. Targeted ARGs tet(T), sul1, and blaCTX-M-1 in liquid hog manure, soil, and water samples were quantified by qPCR. Conventional PCR was used to detect mcr-1 and mcr-2. ARGs in control plots were detected despite the absence of manure, representing an environmental reservoir of resistant microorganisms. The manure application rate higher than 39 m3/ha increased tet(T) and sul1 gene concentrations in soil for more than 180 days. Tillage practices had no impact on ARG concentrations in soil and water samples. The blaCTX-M-1 gene was only detected in seven water samples in 2016, but no link was established with the treatments. The mcr-1 and mcr-2 genes were not detected in all tested samples. This study demonstrated that tet(T) and sul1 gene concentrations increased in soil after liquid hog manure application as well as in drainage water in the next weeks.

The aim of this study was to evaluate the potential of micronutrients and feed additives to modulate intestinal microbiota and systemic and mucosal immune responses in weaned pigs infected with Salmonella. At weaning, 32 litters of 12 piglets each were allocated to four dietary treatments: 1) control diet (CTRL), 2) CTRL supplemented with chlortetracycline (ATB), 3) CTRL supplemented with a cocktail of feed additives (CKTL); and 4) CKTL diet containing bovine colostrum in replacement of spray-dry animal plasma (CKTL+COL). The CKTL supplement included cranberry extract, encapsulated carvacrol and yeast-derived products and an enriched selenium and vitamin premix. Three weeks after weaning, four pigs per litter were orally inoculated with Salmonella Typhimurium DT104. Half of them were euthanized 3 days post-infection (dpi) and the other half, 7 dpi. The expression of IL6, TNF, IL8, monocyte chemoattractant protein 1 (MCP1), IFNG, cyclooxygenase 2 (COX2), glutathione peroxidase 2 (GPX2) and β-defensin 2 (DEFB2) showed a peaked response at 3 dpi (P 0.05). Results also revealed that DEFB2 expression was higher at 3 dpi in CTRL and CKTL groups than in ATB (P = 0.01 and 0.06, respectively) while GPX2 gene was markedly increased at 3 and 7 dpi in pigs fed CKTL or CKTL+COL diet compared to CTRL pigs (P 0.05). In piglets fed CKTL or CKTL+COL diet, intestinal changes in microbial communities were less pronounced after exposure to Salmonella compared to CTRL and progressed faster toward the status before Salmonella challenge (AMOVA P 0.01). Furthermore, the relative abundance of several families was either up- or down-regulated in pigs fed CKTL or CKTL+COL diet after Salmonella challenge. In conclusion, weaning diet enriched with bovine colostrum, vitamins and mixture of feed additives mitigated the influence of Salmonella infection on intestinal microbial populations and modulate systemic and intestinal immune defences.

The intestinal microbiota plays several important roles in pig health and growth. The aim of the current study was to characterize the changes in the fecal microbiota diversity and composition of weaned piglets following an oral challenge with an ETEC: F4 strain and/or a treatment with colistin sulfate (CS). Twenty-eight piglets were used in this experiment and were divided into four groups: challenged untreated, challenged treated, unchallenged treated, and unchallenged untreated. Rectal swab samples were collected at five sampling times throughout the study. Total genomic DNA was used to assess the fecal microbiota diversity and composition using the V4 region of the 16S rRNA gene. The relative abundance, the composition, and the community structure of piglet fecal microbiota was highly affected by the ETEC: F4 challenge throughout the experiment, while the oral treatment with CS, a narrow spectrum antibiotic, resulted in a significant decrease of E. coli/Shigella populations during the treatment period only. This study was the first to identify some gut microbiota subgroups (e.g., Streptococcus, Lachnospiraceae) that are associated with healthy piglets as compared to ETEC: F4 challenged animals. These key findings might contribute to the development of alternative strategies to reduce the use of antimicrobials in the control of post-weaning diarrhea in pigs.

The Canadian Food Inspection Agency (CFIA), as part of the modernization of its inspection system, is developing a risk assessment model with the goal of evaluating the most important food safety-related risk factors associated with the various types of food establishments under its jurisdiction. Ultimately, this new risk assessment model will assist CFIA in allocating its inspection resources according to the level of risk associated with each establishment. As a first step, key risk factors need to be identified. The objective of the current study was thus to identify and evaluate the importance of food safety-related risk factors that could be included in a risk assessment model. An initial literature search was used to identify these risk factors. Thereafter, 75 Canadian food safety experts were asked to assess the relative importance of the 155 identified risk factors with respect to food safety. This step was carried out using a web-based questionnaire in which risk factors had to be assessed by experts using a ten-point Likert-type scale. One risk factor (“management commitment”) received a median score of 10, while median score of 9, 8.5 and 8, and below 8 were attributed to 42, 77 and 35 of the risk factors listed, respectively. A company's commitment towards food safety was identified as an important risk factor contributing to the magnitude of the risk attributed to a food establishment. Many factors related to the performance of an establishment's preventive control plans were also scored high by experts, such as sanitation, hygiene practices, calibration and employee training. The median interquartile range in risk factor scoring generally did not exceed 2, and the respondent profile (work experience, employer and/or commodity-based expertise) did not have a strong influence on score results based on Kruskal–Wallis tests. This observation suggests that, despite their different backgrounds, experts’ opinions were relatively consistent and comparable when scoring the impact of various risk factors towards food safety. These survey outcomes represent useful information to aid in the design and implementation of risk assessment models for food establishments.

Toxoplasmosis is a zoonosis of public health concern worldwide. Toxoplasma gondii can be transmitted to humans through the consumption of raw or undercooked meat, but little is known about...

The ever-increasing problem of antibiotic resistance makes routine use of antibiotics in animal production no longer considered as a reasonable and viable practice. The Chicken Farmers of Canada have developed and are implementing an Antimicrobial Use Reduction Strategy, which has the ultimate goal of eliminating the preventive use of medically important antibiotics in broiler chicken and turkey production. However, very little is known about the real overall impact of an antibiotic use reduction strategy in complex ecosystems, such as the bird intestine or the commercial broiler chicken farm. The main objectives of the present study were to compare the abundance of antibiotic resistance-encoding genes, characterize the intestinal microbiota composition, and evaluate the presence of Clostridium perfringens, in six commercial poultry farms adopting short-term antibiotic withdrawal and long-term judicious use strategy. Implementing an antibiotic-free program over a 15-months period did not reduce the abundance of many antibiotic resistance-encoding genes, whereas the judicious use of antibiotics over 6 years was found effective. The short-term antibiotic withdrawal and the long-term judicious use strategy altered the intestinal microbiota composition, with the Ruminococcaceae and Lachnospiraceae families being negatively impacted. These findings are in agreement with the lower production performance and with the increased C. perfringens populations observed for farms phasing out the use of antibiotics. Adopting a conventional rearing program on commercial broiler chicken farms selected for specific antibiotic resistance-encoding genes in many barns. This study highlights the potential impacts of different rearing programs in poultry production and will help guide future policies in order to reduce the use of antibiotics while maintaining production performance.

Background: Tail-biting (TB) is a serious behavioral disorder in pigs. It is defined as a pig chewing the tail of another pig. It is an important challenge in swine production as it impacts the animal welfare, its health and the economics and safety of the pork meat supply chain. Some treatments have been proposed but have not proven optimal. Nutrition, feed type and composition, appears to be an important factor in TB behavior, perhaps by modulating the intestinal microbiota (IM). In humans, IM is increasingly recognized as a modulator of behavior. Our aim was to assess an association between TB behavior and IM in pigs through comparisons of IM in groups of biter or bitten pigs to the IM in a non-biter and non-bitten negative control group, and through comparisons of IM between the biter and bitten groups. Each group, composed of 12 pigs, was formed at the beginning of the growing/finishing phase based on a target behavior analysis centered on TB behavior for the biter group and a score of damages caused to the tail for the bitten group. Fecal and blood samples were collected from each pig during a TB episode, at time 0, t0, and after a TB episode, four weeks later, at time 1, t1. Serum cortisol level was determined by ELISA and used as an indicator of stress. The pig’s fecal microbiota was analyzed from DNA extracted from freshly collected fecal matter using amplicon sequencing of the V4 hypervariable region of the 16S rRNA gene. Results: Serum cortisol levels were significantly higher in either the biter or bitten pig groups compared to the negative control group ( p =0.02 and p =0.01, respectively). Interestingly, no significant difference was revealed between the biter and bitten groups. The microbiota alpha-diversity was not significantly different between all groups, biter, bitten and negative control. Analyses of beta-diversity, however, revealed a significant difference between either the biter or the bitten group in comparison to the negative control group in terms of structure and composition of the microbiota. Lactobacillus were significantly more abundant in the negative control group compared to the two other groups ( p =0.001). No significant difference was revealed between the biter and bitten groups. Quantitative real-time PCR (qPCR) confirmed that lactobacilli were more abundant in the negative control group. Conclusions: This study demonstrates that TB behavior is associated to the IM composition in pigs.

The Canadian Food Inspection Agency (CFIA) is developing a risk assessment model aimed at quantifying the food safety risk associated with food establishments under its jurisdiction. To support the development of this model, the current study was undertaken to quantify the relative importance of selected criteria considered for inclusion in the model. This process also aimed at estimating the risk associated with specific clusters of criteria. Overall, 173 criteria were presented to experts during a two-round face-to-face expert elicitation to estimate their relative risk to human health. Twenty-nine Canadian experts participated in the expert elicitation including members from academia (31%), industry (31%), and government (38%). A good consensus on the relative risks given to most criteria and clusters of criteria was achieved, and experts assessed them as significantly affecting the risk related to a food establishment. None of the experts expressed opposition to the inclusion of any criterion or to the way they were clustered. Experts assigned a relative risk of ≤4, of 4–8, and of ≥8–67% (116), 29.5% (51), and 3.5% (6) of the 173 criteria identified, respectively. Those having the highest impact on establishment food safety risk were: historical food safety recalls and lack of compliance for the sanitation program, the control of critical control points, followed by the equipment maintenance and calibration program, and the general food hygiene program. Having a sampling plan with trend analysis and follow-up actions was considered as an important mitigation factor. As a result, the median values calculated for each criterion and cluster will be used in the new Canadian Food Inspection Agency Establishment-based risk assessment model to support the allocation of inspection resources based on risk.

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.

The safety of livestock feed is recognized worldwide as a prerequisite for the protection of animal and human health. In this context, the Canadian Food Inspection Agency is developing an Establishment-based Risk Assessment model for livestock feed mills (ERA-Feed Mill) to assist in the allocation of inspection resources based on feed safety risk. The objectives of the present study were to identify and select animal health and food safety-related risk factors along with their assessment criteria, pertaining to Canadian feed mill practices, to be included in the ERA-Feed Mill model. To do so, a review of the scientific literature and consultations with feed experts were conducted. A final list of 34 risk factors was generated, 21 identified from the scientific literature and 13 from feed expert advice. Risk factors were grouped into three clusters: inherent risk factors, mitigation factors and compliance factors for which 4, 10 and 20 factors were identified, respectively. Criteria for quantitatively assessing each risk factor were defined based on common practices found in the Canadian feed industry. These findings contributed to the initial steps of the CFIA's ERA-Feed Mill model development. By assessing the feed safety risk factors related to feed mills in Canada, this tool will help inform the CFIA on the level of oversight required to manage these risks, and will contribute to the production and maintenance of healthy livestock and the production of safe food.

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 χ²) and human clinical cases (P < 0.01, exact χ²), 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 χ²). 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 shows that the presence of disinfectants resistance genes is an important contributing factor.

This study was carried out to evaluate the prevalence of Salmonella serogroups and serotypes and their virulence gene carriage in pig fecal samples from farms and slaughterhouses in some southern provinces of Vietnam. The presence of Salmonella was assessed based on culture enrichment of the collected samples and biochemical and serological analyses; 27.7% (51) of 184 samples were posititve for Salmonella. Based on the availability of antisera, serogroups were determined for 61% (31) of 51 isolates. Twenty isolates belonging to Salmonella serotypes Typhimurium (10 isolates), Anatum (8 isolates), Senftenberg (7 isolates), Paratyphi B (3 isolates), Paratyphi A (1 isolate), Montevideo (1 isolate), and Saintpaul (1 isolate) were further characterized by a multiplex PCR protocol targeting Salmonella invasion A and virulence plasmid C genes ( invA and spvC, respectively). Individual PCR assays were developed to detect genes for Salmonella enterotoxin ( stn) , Salmonella outer protein B ( sopB), and Salmonella fimbriae ( pef). Various carriage patterns were identified among tested isolates. The invA and sopB genes were found in all isolates, and the stn gene was found in 95% of the isolates. The spvC gene was found in only 5% of the Salmonella Typhimurium isolates. None of the isolates were positive for the pef gene. Among all isolates, the predominant genotypic virulence profile (virulotype) was characterized by the concomitant presence of invA, sopB, and stn in carrier strains. In contrast, two virulotypes comprising either invA, sopB, spvC, and stn or invA and sopB were identified for the Salmonella Typhimurium isolates. Virulotypes made up of multiple virulence genes were predominant in most Salmonella strains tested in this study, indicating that pigs might act as a reservoir for these virulent strains.

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.

The Canadian Food Inspection Agency (CFIA) is developing a risk assessment model for food establishments. Previous research on the significance of food safety risk factors determined by literature review and expert advice served as the bases for the current study, to further refine, discriminate and select the most important criteria to be included in the model. This process considered the availability of data sources, the clarity and measurability of the selected factors, undertook the elimination of lower-rated risk factors and grouped those with similar focus of attention, enabling the selection of a final list of risk factors for the model. A method of assessment for the remaining factors was then proposed to allow the quantification of individual risk factors within the model. From the 155 risk factors initially identified, 17 consolidated factors were kept and will be considered for the development of the risk assessment model.

Decreasing the health burden caused by foodborne pathogens is challenging and it depends on the identification of the most significant hazards and food sources causing illnesses, so adequate mitigation strategies can be implemented. In this regard, the Canadian Food Inspection Agency (CFIA) has developed the Establishment-based Risk Assessment (ERA) model, so that a more effective and efficient allocation of resources can be assigned to the highest food safety risk areas. To assess risk, the model considers the type of food sub-products being manufactured by establishments and its scope is limited to the 17 most important foodborne pathogens representing the highest level of food safety risk. However, the information on source attribution at the sub-product level based on a structured approach is limited. To overcome this challenge, an expert elicitation was conducted in 2016 to estimate the relative contribution and associated certainty of each sub-product for 31 pathogen-commodity combinations to the total Canadian health burden associated with foodborne illnesses (expressed in DALYs). These DALYs represent 78% of the total Canadian health burden associated with federally-regulated food commodities considered within the model. A total of 49 Canadian experts recruited using a “snow ball” sampling strategy participated in the study by completing an electronic survey. Results of the elicitation displayed variable levels of health burden allocation between the pathogens and the different commodity sub-products. Assessment of the certainty levels showed some combinations being evaluated with more confidence (e.g., Campylobacter and eggs/poultry sub-products) than others, where a bimodal distribution of certainty was observed (e.g., Toxoplasma in pork sub-products). Furthermore, no participant raised concerns on the food classification scheme, suggesting their agreement with the proposed sub-products categorization of the elicitation. Relative contribution estimates will be included in the CFIA ERA model and used to enhance its applicability for risk prioritization and effective resource allocation during food establishment inspections. While substantial uncertainty around the central tendency estimates was found, these estimates provide a good basis for regulatory oversight and public health policy.

Salmonella enterica serovar Typhimurium is an important pathogen in swine and is also a frequently reported zoonotic agent. The objective of this study was to characterize isolates of S. enterica serovar Typhimurium associated with septicemia in swine and to compare them to isolates recovered from clinically healthy pigs. We were particularly interested in comparing the two groups of isolates for their ability to adhere to and invade host cells, to be phagocytized and survive in monocyte cells, to induce apoptosis, and to adhere to intestinal mucus. Their surface properties were also evaluated by interactions with solvents. The isolates recovered from diseased animals were shown to invade intestinal epithelial cell lines at a higher rate ( P = 0.003) than isolates from healthy pigs. Septicemic isolates were phagocytized by human monocytes at a higher rate than isolates from healthy pigs ( P = 0.009). The mean percentages of phagocytosis were significantly lower for human monocytes than for porcine monocytes ( P = 0.02 and P = 0.008, respectively) for isolates from both diseased and healthy animals. Healthy animal isolates were phagocytized more by porcine monocytes at 15 min ( P = 0.02) than septicemic isolates. No difference between isolates from septicemic pigs and isolates from healthy pigs was detected for other tested parameters. These results suggest that septicemic isolates have a particular pattern of invasion.

An observational study was conducted to estimate prevalence and risk factors for carcass contamination by Salmonella and Campylobacter spp. in 60 lots of turkey slaughtered over 10 months in the province of Quebec, Canada. Carcass contamination was evaluated by the carcass rinse technique for about 30 birds per lot. Exposure to potential risk factors was evaluated with questionnaires, meteorological data, and cecal cultures. Multivariable binomial negative regression models were used for risk factor analysis. Prevalence of Salmonella-positive carcasses was 31.2% (95% confidence interval, 22.8 to 39.5%). Variables positively associated (Por = 0.05) with the proportion of lot-positive carcasses wereor =0.5% of carcass condemnation due to various pathologies, cecal samples positive for Salmonella, low wind speed during transportation, closure of lateral curtains of truck during transportation, and slaughtering on a weekday other than Monday. When only Salmonella-positive cecal culture lots were considered, the proportion of carcasses positive for Salmonella was significantly higher in lots exposed to a5 degrees C outside temperature variation during transportation, slaughtered on a weekday other than Monday, and in whichor = 4% of carcasses had visible contamination. Prevalence of Campylobacter-positive carcasses was 36.9% (95% confidence interval, 27.6 to 46.3%). The proportion of positive carcasses was significantly higher in lots with Campylobacter-positive cecal cultures and lots undergoingor =2 h of transit to slaughterhouse. For lots with Campylobacter-positive cecal cultures, variables significantly associated with an increased incidence of carcass contamination were de4% of carcasses with visible contamination, crating foror =8 h before slaughtering, and no antimicrobials used during rearing.

The recent emergence of multidrug-resistant Salmonella enterica subspecies enterica serotype Typhimurium phage-type DT104 represents a challenge to health workers from both human and veterinary medicine. In an effort to develop effective control strategies, it is vital to characterize accurately the extent of genetic and phenotypic variation present in the pathogen population. While previous studies have focused on disease-associated populations, we report the genetic diversity and the diversity in antimicrobial resistance associated with asymptomatic Salmonella Typhimurium DT104 isolates found in pigs. Using pulsed-field gel electrophoresis (XbaI and SpeI), we identified 62 different genotypes associated to 13 different antimicrobial resistant phenotypes among 80 asymptomatic DT104 isolates collected from the Canadian swine industry. When rarefaction curves of a subsample the asymptomatic isolates were compared to that of disease-associated isolates from a similar spatial and temporal scale, we identified significantly more genotypes among the asymptomatic populations with 27 PFGE patterns against 23.0+/-1.4 (95% confidence intervals) in the latter. Also, using Simpson's diversity index, we observed considerably higher genetic and phenotypic diversity in the asymptomatic isolates within herds and detected possible patterns of periodic selection within the disease-associated population. We thus concluded that an important aspect of Salmonella population structure and ecology is overlooked in investigations of disease-associated isolates.

Pathogenic microorganisms in manure represents a potential hazard to human and animal. Few data describing the microbiological content of liquid hog manure intended for spreading are available in the scientific literature. The objective of this project was to verify the presence and estimate the persistence of Escherichia coli , Salmonella spp . , Yersinia enterocolitica and Cryptosporidium spp. in liquid hog manure from storages under conditions typical of commercial swine production in Quebec. E. coli content of liquid hog manure taken during the spreading period in the 32 hog operations varied between 0 and 5.52 log 10 CFU/g with a 95% confidence interval of 3.16–4.23 log 10 CFU/g. Salmonella spp., Y. enterocolitica and Cryptosporidium spp. were detected in 37%, 9% and 3% samples, respectively. Under the conditions of this experiment, the predicted number of days required to obtain a 90% reduction of E. coli populations varied between 15 and 26 days, while the predicted storage period necessary to reach undetectable levels was 54–114 days. The maximal persistence of Salmonella observed in this study was 88 days. A 73-day storage time was insufficient for the elimination of Y. enterocolitica .

The objective of this study was to evaluate the efficiency of a low temperature anaerobic treatment to reduce viable populations of indicator microorganisms (total coliforms, Escherichia coli) and the presence of selected pathogens (Salmonella, Yersinia enterocolitica, Cryptosporidium and Giardia) in swine slurries from different sources. Experiments were carried out in 40 l Sequencing Batch Reactors (SBRs). Experimental results indicated that anaerobic digestion of swine manure slurry at 20 � C for 20 days in an intermittently fed SBR: (1) reduced indigenous populations of total coliforms by 97.94–100%; (2) reduced indigenous populations of E. coli by 99.67–100%; (3) resulted in undetectable levels of indigenous strains of Salmonella, Cryptosporidium, and Giardia .I t can be considered as a promising method for reducing indigenous indicator and pathogenic microorganisms populations in liquid swine manure slurries. � 2005 Elsevier Ltd. All rights reserved.

Background: Campylobacter jejuni is responsible for human foodborne enteritis. This bacterium is a remarkable colonizer of the chicken gut, with some strains outcompeting others for colonization. To better understand this phenomenon, the objective of this study was to extensively characterize the phenotypic performance of C. jejuni chicken strains and associate their gut colonizing ability with specific genes. Results: C. jejuni isolates (n = 45) previously analyzed for the presence of chicken colonization associated genes were further characterized for phenotypic properties influencing colonization: autoagglutination and chemotaxis as well as adhesion to and invasion of primary chicken caecal cells. This allowed strains to be ranked according to their in vitro performance. After their in vitro capacity to outcompete was demonstrated in vivo, strains were then typed by comparative genomic fingerprinting (CGF). In vitro phenotypical properties displayed a linear variability among the tested strains. Strains possessing higher scores for phenotypical properties were able to outcompete others during chicken colonization trials. When the gene content of strains was compared, some were associated with different phenotypical scores and thus with different outcompeting capacities. Use of CGF profiles showed an extensive genetic variability among the studied strains and suggested that the outcompeting capacity is not predictable by CGF profile. Conclusion: This study revealed a wide array of phenotypes present in C. jejuni strains, even though they were all recovered from chicken caecum. Each strain was classified according to its in vitro competitive potential and its capacity to compete for chicken gut colonization was associated with specific genes. This study also exposed the disparity existing between genetic typing and phenotypical behavior of C. jejuni strains., [À l'origine dans / Was originally part of : Fac. Méd. vétérinaire - Chaire de recherche en salubrité des viandes]

Liquid hog manure is routinely applied to farm land as a crop fertilizer. However, this practice raises food safety concerns, especially when manure is used on fruit and vegetable crops. The objectives of this project were to evaluate the persistence of Escherichia coli and Salmonella in surface soil after application of liquid hog manure to fields where pickling cucumbers were grown and to verify the microbiological quality of harvested cucumbers. Mineral fertilizers were replaced by liquid hog manure at various ratios in the production of pickling cucumbers in a 3-year field study. The experimental design was a randomized complete block comprising four replicates in sandy loam (years 1, 2, and 3) and loamy sand (year 3). Soil samples were taken at a depth of 20 cm every 2 weeks after June application of organic and inorganic fertilizers. Vegetable samples were also taken at harvest time. Liquid hog manure, soil, and vegetable (washed and unwashed) samples were analyzed for the presence of Salmonella and E. coli. An exponential decrease of E. coli populations was observed in surface soil after the application of manure. The estimated average time required to reach undetectable concentrations of E. coli in sandy loam varied from 56 to 70 days, whereas the absence of E. coli was estimated at 77 days in loamy sand. The maximal Salmonella persistence in soil was 54 days. E. coli and Salmonella were not detected in any vegetable samples.

Campylobacter spp. were recovered from 660 (77.6%) of 850 swine cecal contents at the abattoir and from 24 (8.6%) of 278 specimens from sporadic cases of human diarrhea during the same period in the same geographical area. Campylobacter coli represented 95.7% of Campylobacter isolates recovered from pigs and 8.3% of those isolated from humans. Genetic profiles were determined by pulsed-field gel electrophoresis (PFGE) using KpnI enzyme to characterize the isolates in combination with phenotypic assays to detect production of cytotoxins, enterotoxins, and hemolysins. Among a subset of isolates (n = 10), up to five colonies from the same animal were characterized by PFGE. In 5 (50%) of 10 of the isolates, more than one genetic profile was observed per pig. Among the 100 isolates from pigs selected for further analysis, 81 different genetic profiles were observed, whereas 20 different genetic profiles were found among the 24 isolates of human origin. Cytotoxicity on Chinese hamster ovary cells was observed in 11 (11%) of 98 isolates from pigs and in 5 (21%) of 24 Campylobacter isolates from humans. No enterotoxin production was detected in Campylobacter isolates in this study, but 17 (71%) of 24 human and 61 (63%) of 97 pig isolates showed hemolytic activity. The study of genotypic and phenotypic profiles of swine and human isolates revealed no epidemiological relationship between isolates. The low genomic relatedness observed between groups of isolates and the weak toxicity level of swine isolates suggest that the hazard of contamination of humans by Campylobacter associated with swine production is low.

This study was designed to review all grossly detectable abnormalities and conditions (GDACs) encountered in poultry in Canadian abattoirs to determine which have potential to cause adverse health effects for the consumer. Review of the literature and consultation with scientists in the field of microbiology, epidemiology, poultry pathology, chemistry, and meat inspection served to generate an inventory of GDACs, and a decision tree containing algorithms was developed to identify GDACs potentially representing a health hazard to consumers. Through the use of the decision tree, GDACs were classified into different categories with regard to the risk they represent to humans. A number of GDACs were identified as being of potential concern from a food safety perspective, namely Erysipelas, fowl cholera, Campylobacteriosis, clostridial diseases, hepatitis/enteritis associated with Helicobacter, Listeriosis, Salmonella infections (nontyphoid infections, Salmonella arizonae, pullorum disease, and fowl typhoid), Staphylococcosis, and Toxoplasmosis. Further characterization--i.e., hazard characterization, exposure assessment, and risk characterization--is required to quantify or better characterize the probability that products derived from affected carcasses may affect the consumer as well as the resulting consequences. Risk assessment is a dynamic process. Results presented in this paper are based on available information and expert opinion. As new information is obtained, the inventory of GDACs and their classification may be modified.

Five porcine finishing units, previously identified as contaminated by Salmonella, were sampled to identify possible sources of contamination and to study the distribution of Salmonella within the herds. A total of 208 environmental samples were taken and 87 samples (42%) were found contaminated by Salmonella spp. Salmonella was recovered from several types of samples. Among these, fecal material from pens, building environment such as doors, floors, ventilation units, dust and farm accessories were most often found positive. Some of the flies and rodents were also positive. Two of the finishing units were part of an integrated production system and the prevalence and distribution of Salmonella spp. at different production steps of the integrated facilities were studied. Forty-one farms were sampled and a total of 1923 faecal samples in randomly selected pens were analysed. One hundred and fifty-one samples (7.9%) were positive for Salmonella spp. Among the farms sampled, 70.7% (29/41) were positive for isolation of Salmonella. The different levels in the integrated production were unevenly contaminated. Replacement sow (15.9%) and finishing unit for gilts (21.9%) were the most contaminated levels. Ten serotypes of Salmonella (n = 132) were identified in the production pyramid with a predominance of Salmonella Derby (37.1%) and Salmonella Typhimurium (34.1%). Pulse Field Gel Electrophoresis analysis of the various isolates from serotypes and Salmonella Typhimurium, Salmonella Derby and Salmonella Anatum showed no variation in the genetic profiles, within each serotype, suggesting a vertical contamination throughout the different production steps.

The purpose of this study was to evaluate the risk for human health associated with pathogenic Escherichia coli isolated from airsacculitis and cellulitis in chickens, by comparing the genotypic and phenotypic profiles of avian E. coli isolates and E. coli strains isolated from sick humans during the same period and in the same geographical area as the avian isolates. A total of 96 isolates and 46 isolates from lesions of cellulitis and airsacculitis, respectively, were obtained. Isolates from the backs of some of the affected and healthy birds and 91 intestinal and extraintestinal isolates from humans with diarrhea, urinary tract infections, or septicemia were examined. The frequency of antimicrobial resistance was in general higher in the avian than in the human isolates. VT1-VT2-Eae and VT2-Eae, pathotypes associated with hemolytic and uremic syndrome and bloody diarrhea in humans, were the most frequently encountered pathotypes in human intestinal isolates but were not recovered from the avian isolates. Aero-Pap-TSH and Aero-TSH were the most frequently encountered pathotypes in avian isolates but were rarely observed in human isolates. No avian isolate was of serogroup O157, whereas many human isolates belonged to this O group. O78 and O2 were the most frequently observed O groups in avian isolates but were rarely found in human isolates. Only two avian isolates demonstrated possible relatedness to human isolates based on pulsed-field gel electrophoresis profiles, but they belonged to different pathotypes. Our results suggest that avian isolates recovered from cellulitis and air sacullitis possess very few of the attributes required to cause diseases in humans. It is also concluded that isolates from cellulitis and airsacculitis do not represent a greater hazard than isolates from the back of healthy birds.

Campylobacter jejuni is an important worldwide foodborne pathogen commonly found as a commensal organism in poultry that can reach high numbers within the gut after colonization. Although information regarding some genes involved in colonization is available, little is known about their distribution in strains isolated specifically from chickens and whether there is a linkage between antimicrobial resistance (AMR) and colonization genes. To assess the distribution and relevance of genes associated with chicken colonization and AMR, a C. jejuni microarray was created to detect 254 genes of interest in colonization and AMR including variants. DNA derived from chicken-specific Campylobacter isolates collected in 2003 (n=29) and 2008 (n=28) was hybridized to the microarray and compared. Hybridization results showed variable colonization-associated gene presence. Acquired AMR genes were low in prevalence whereas chemotaxis receptors, arsenic resistance genes, as well as genes from the cell envelope and flagella functional groups were highly variable in their presence. Strains clustered into two groups, each linked to different control strains, 81116 and NCTC11168. Clustering was found to be independent of collection time. We also show that AMR weakly associated with the CJ0628 and arsR genes. Although other studies have implicated numerous genes associated with C. jejuni chicken colonization, our data on chicken-specific isolates suggest the opposite. The enormous variability in presumed colonization gene prevalence in our chicken isolates suggests that many are of lesser importance than previously thought. Alternatively, this also suggests that combinations of genes may be required for natural colonization of chicken intestines.

This study describes and measures the impact of different compositions and finishes of stainless steel used in equipment in the meat industry on the transfer of natural flora and selected pathogens from artificially contaminated pork skin. It is known that the adhesion to surfaces of Listeria monocytogenes and Salmonella, 2 pathogens frequently found in contaminated pork meat, depends on the nature and roughness of the surface. Our results show no statistically significant differences in microbial transfer regardless of the types of stainless steel considered, with the highest measured transfer difference being 0.18 log colony-forming units (CFUs)/800 cm(2). Moreover, no differences in total microbial community were observed after transfer on the 5 types of stainless steel using single-strand conformation polymorphism (SSCP). It was concluded that the different characteristics of the stainless steel tested did not affect the initial bacterial transfer in this study.La présente étude vise à décrire et mesurer l’impact de différentes compositions et de différents finis d’acier inoxydable utilisés dans les équipements de l’industrie de la viande sur le transfert de la flore naturelle et d’agents pathogènes sélectionnés provenant de peau de porc contaminée artificiellement. Il est connu que l’adhésion de