Applicability and feasibility of systematic review for performing evidence-based risk assessment in food and feed safety.

Food and feed safety risk assessment uses multi-parameter models to evaluate the likelihood of adverse events associated with exposure to hazards in human health, plant health, animal health, animal welfare, and the environment. Systematic review and meta-analysis are established methods for answering questions in health care, and can be implemented to minimize biases in food and feed safety risk assessment. However, no methodological frameworks exist for refining risk assessment multi-parameter models into questions suitable for systematic review, and use of meta-analysis to estimate all parameters required by a risk model may not be always feasible. This paper describes novel approaches for determining question suitability and for prioritizing questions for systematic review in this area. Risk assessment questions that aim to estimate a parameter are likely to be suitable for systematic review. Such questions can be structured by their "key elements" [e.g., for intervention questions, the population(s), intervention(s), comparator(s), and outcome(s)]. Prioritization of questions to be addressed by systematic review relies on the likely impact and related uncertainty of individual parameters in the risk model. This approach to planning and prioritizing systematic review seems to have useful implications for producing evidence-based food and feed safety risk assessment.

The zoonotic potential of Mycobacterium avium ssp. paratuberculosis: a systematic review and meta-analyses of the evidence.

This systematic review-meta-analysis appraises and summarizes all the available research (128 papers) on the zoonotic potential of Mycobacterium avium ssp. paratuberculosis. The latter has been debated for a century due to pathogenic and clinical similarities between Johne's disease in ruminants and Crohn's disease (108 studies) in humans and recently for involvement in other human diseases; human immunodeficiency virus (HIV) infection (2), sarcoidosis (3), diabetes mellitus type 1 (T1DM) (7) and type 2 (3), multiple sclerosis (5) and Hashimoto's thyroiditis (2). Meta-analytical results indicated a significant positive association, consistently across different laboratory methods for Crohn's disease [odds ratio (OR) range 4·26-8·44], T1DM (OR range 2·91-9·95) and multiple sclerosis (OR range 6·5-7·99). The latter two and the thyroiditis hypothesis require further investigation to confirm the association. Meta-regression of Crohn's disease studies using DNA detection methods indicated that choice of primers and sampling frame (e.g. general population vs. hospital-based sample) explained a significant proportion of heterogeneity. Other epidemiological studies demonstrated a lack of association between high-risk occupations and development of Crohn's disease. Due to knowledge gaps in understanding the role of M. paratuberculosis in the development or progression of human disease, the evidence at present is not strong enough to inform the potential public health impact of M. paratuberculosis exposure.

Evaluating interventions against Salmonella in broiler chickens: applying synthesis research in support of quantitative exposure assessment.

A scoping study and systematic review-meta-analyses (SR-MAs) were conducted to evaluate the effectiveness of various interventions for Salmonella in broiler chicken, from grow-out farm to secondary processing. The resulting information was used to inform a quantitative exposure assessment (QEA) comparing various control options within the context of broiler chicken production in Ontario, Canada. Multiple scenarios, including use of two separate on-farm interventions (CF3 competitive exclusion culture and a 2% lactose water additive), a package of processing interventions (a sodium hydroxide scald water disinfectant, a chlorinated post-evisceration spray, a trisodium phosphate pre-chill spray and chlorinated immersion chilling) a package consisting of these farm and processing interventions and a hypothetical scenario (reductions in between-flock prevalence and post-transport concentration), were simulated and compared to a baseline scenario. The package of on-farm and processing interventions was the most effective in achieving relative reductions (compared to baseline with no interventions) in the concentration and prevalence of Salmonella by the end of chilling ranging from 89·94% to 99·87% and 43·88% to 87·78%, respectively. Contaminated carcasses entering defeathering, reductions in concentration due to scalding and post-evisceration washing, and the potential for cross-contamination during chilling had the largest influence on the model outcomes under the current assumptions. Scoping study provided a transparent process for mapping out and selecting promising interventions, while SR-MA was useful for generating more precise and robust intervention effect estimates for QEA. Realization of the full potential of these methods was hampered by low methodological soundness and reporting of primary research in this area.

Zoonotic bacteria, antimicrobial use and antimicrobial resistance in ornamental fish: a systematic review of the existing research and survey of aquaculture-allied professionals.

Using systematic review methodology, global research reporting the frequency of zoonotic bacterial pathogens, antimicrobial use (AMU) and antimicrobial resistance (AMR) in ornamental fish, and human illness due to exposure to ornamental fish, was examined. A survey was performed to elicit opinions of aquaculture-allied personnel on the frequency of AMU and AMR in ornamental fish. The most commonly reported sporadic human infections were associated with Mycobacterium marinum, while Salmonella Paratyphi B var. Java was implicated in all reported outbreaks. Aeromonas spp. were most frequently investigated (n=10 studies) in 25 studies surveying ornamental fish from various sources. High levels of resistance were reported to amoxicillin, penicillin, tetracycline and oxytetracycline, which was also in agreement with the survey respondents' views. Studies on AMU were not found in our review. Survey respondents reported frequent use of quinolones, followed by tetracyclines, nitrofurans, and aminoglycosides. Recommendations for future surveillance and public education efforts are presented.

A systematic review/meta-analysis of primary research investigating swine, pork or pork products as a source of zoonotic hepatitis E virus.

The objectives of our study were to identify and categorize primary research investigating swine/pork as a source of zoonotic hepatitis E virus (HEV) using the relatively new technique of scoping study, and to investigate the potential association between human exposure to swine/pork and HEV infection quantitatively using systematic review/meta-analysis methodology. From 1890 initially identified abstracts, 327 were considered for the review. Five study design types (cross-sectional, prevalence, genotyping, case-report and experimental transmission studies) were identified. A significant association between occupational exposure to swine and human HEV IgG seropositivity was reported in 10/13 cross-sectional studies. The association reported between pork consumption and HEV IgG seropositivity was inconsistent. The quantification of viral load in swine and retail pork, viral load required for infection in primates, cohort and case-control studies in humans, and formal risk assessment are recommended before specific public-health policy actions are taken.

Choices, choices: the application of multi-criteria decision analysis to a food safety decision-making problem.

In the food safety arena, the decision-making process can be especially difficult. Decision makers are often faced with social and fiscal pressures when attempting to identify an appropriate balance among several choices. Concurrently, policy and decision makers in microbial food safety are under increasing pressure to demonstrate that their policies and decisions are made using transparent and accountable processes. In this article, we present a multi-criteria decision analysis approach that can be used to address the problem of trying to select a food safety intervention while balancing various criteria. Criteria that are important when selecting an intervention were determined, as a result of an expert consultation, to include effectiveness, cost, weight of evidence, and practicality associated with the interventions. The multi-criteria decision analysis approach we present is able to consider these criteria and arrive at a ranking of interventions. It can also provide a clear justification for the ranking as well as demonstrate to stakeholders, through a scenario analysis approach, how to potentially converge toward common ground. While this article focuses on the problem of selecting food safety interventions, the range of applications in the food safety arena is truly diverse and can be a significant tool in assisting decisions that need to be coherent, transparent, and justifiable. Most importantly, it is a significant contributor when there is a need to strike a fine balance between various potentially competing alternatives and/or stakeholder groups.

Feeding management practices and feed characteristics associated with Salmonella prevalence in live and slaughtered market-weight finisher swine: a systematic review and summation of evidence from 1950 to 2005.

This review summarizes evidence for associations between Salmonella prevalence in market-weight swine and changes in feeding management practices or feed characteristics. A systematic review of the topic was conducted with the goal of minimizing the impact of bias on the review conclusions. Potential interventions included feed withdrawal from swine prior to slaughter, feed acidification, heat treatment of feed, pelletized feed versus mash, course versus fine grind, and wet versus dry feeds. In the reviewed literature, Salmonella prevalence was measured either by culture or by the presence of antibodies to Salmonella. The evidentiary value of studies was assessed, and studies that failed to meet predetermined standards were excluded. 7694 potentially relevant references were identified by an extensive literature search; however, 2623 references that were not published in English were excluded, because funds for translation were not available. Of the remaining references, only 277 were considered relevant to the review topic by two independent reviewers, and assessed for methodological quality. During quality assessment, 233 references were excluded because they failed to report design features that limit the introduction of bias or were conducted in a non-target population such as gnotobiotic, neonatal, nursery, or recently weaned pigs and sows. Forty-four publications passed the quality assessment conducted by 2 independent reviewers, but only 15 of the 44 publications reported studies that tested hypotheses associated with feeding management practices and feed characteristics and Salmonella prevalence in market-weight swine. The most common study design was cross-sectional (7/15). The included studies failed to provide strong evidence of an association between any of the potential interventions and Salmonella prevalence, due to the potential for confounding, and the failure to document temporal association between the intervention and Salmonella prevalence. The strongest evidence of an association was found for feed form, i.e. the use of non-pelleted may be potential interventions associated with reduced Salmonella prevalence. The uncertainty is primarily based on studies containing moderate to low evidentiary value or insufficient numbers of tested individuals, resulting in a low degree of confidence that results could be extrapolated to the target population. Therefore, the conclusion of the review is that there should be a low level of comfort among qualified scientists that the claimed association between non-pelleted feed and reduced Salmonella prevalence is scientifically valid. There is no strong evidence regarding associations between presence of Salmonella and the other feed characteristics examined.

Factors influencing the prevalence of Salmonella spp. in swine farms: a meta-analysis approach.

A systematic review and meta-analysis was conducted to identify study-level variables that could explain the variation in apparent Salmonella spp. prevalence estimates. Electronic and non-electronic literature searches from 1990 until 2005 were carried out to identify all studies related to the prevalence of subclinical Salmonella infection in swine. The searches were restricted to studies published in English, Spanish, and French. Clinical trials or any other study where an intervention was evaluated were excluded from this analysis. A template was designed to retrieve the most relevant variables and data abstraction was performed in duplicate. A total of 98 papers containing 82 animal-level and 156 farm-level studies were used in the analyses. The median farm-level and animal-level prevalences were 59% and 17%, respectively. Meta-regression analyses were carried out on both farm and animal-level data. Diagnostic procedure, sample size, and country where study was conducted were the three most important predictors in explaining the differences in Salmonella prevalences between studies. When compared to a farm with a apparent prevalence of 50% determined by the blood ELISA, prevalences based on culture of fecal samples were 39% lower and prevalences based on cecum and tissue cultures were 16% and 19% lower, respectively. Similar to farm-level models, animal-level models did not show any difference among serological tests and prevalence values based culture procedures were, on average, 9% lower than those from serological tests. Sample size was negatively associated with prevalence estimates. In conclusion, the methodology was useful for identifying and quantifying sources of variation in Salmonella apparent prevalence among studies and for establishing prevalence distributions that could be used as input parameters in risk assessment and decision models. The analysis provides some guidelines when interpreting and comparing apparent Salmonella prevalence results from studies using different study designs.

Risk Profile of Hepatitis E Virus from Pigs or Pork in Canada.

The role and importance of pigs and pork as sources of zoonotic hepatitis E virus (HEV) has been debated in Canada and abroad for over 20 years. To further investigate this question, we compiled data to populate a risk profile for HEV in pigs or pork in Canada. We organized the risk profile (RP) using the headings prescribed for a foodborne microbial risk assessment and used research synthesis methods and inputs wherever possible in populating the fields of this RP. A scoping review of potential public health risks of HEV, and two Canadian field surveys sampling finisher pigs, and retail pork chops and pork livers, provided inputs to inform this RP. We calculated summary estimates of prevalence using the Comprehensive Meta-analysis 3 software, employing the method of moments. Overall, we found the incidence of sporadic locally acquired hepatitis E in Canada, compiled from peer-reviewed literature or from diagnosis at the National Microbiology Laboratory to be low relative to other non-endemic countries. In contrast, we found the prevalence of detection of HEV RNA in pigs and retail pork livers, to be comparable to that reported in the USA and Europe. We drafted risk categories (high/medium/low) for acquiring clinical hepatitis E from exposure to pigs or pork in Canada and hypothesize that the proportion of the Canadian population at high risk from either exposure is relatively small.

The process of systematic review and its application in agri-food public-health.

Foodborne illness is an important public-health concern. Livestock operations represent the original source of many foodborne pathogens. Policy- and decision-makers in the area of agri-food public-health need dependable information on interventions to reduce foodborne diseases. While individual studies might be weak or reach contradictory conclusions, the body of information contained in all studies might reveal a clearer picture of the state of knowledge. A formal process has been developed for conducting systematic reviews of the human healthcare literature. Systematic reviews differ from traditional narrative reviews in that systematic reviews follow a structured research protocol to reduce sources of bias at all stages of the review. This includes the objective, the literature search, the identification of relevant literature, quality assessment of relevant studies, summarization or statistical analysis of data, and conclusions. To date, systematic reviews have not been widely used in agri-food public-health. Existing systematic reviews on agri-food public-health topics revealed a scarcity of rigorously conducted intervention research, indicating a need for additional high quality primary studies. The specific protocols used to conduct systematic reviews in agri-food public-health need to accommodate the use of challenge studies and observational studies, the lack of randomized controlled trials, and the clustering of animal populations.

The potential Public Health Impact of Mycobacterium avium ssp. paratuberculosis: Global Opinion Survey of Topic Specialists.

Global research knowledge has accumulated over the past few decades, and there is reasonable evidence for a positive association between Mycobacterium avium spp. paratuberculosis and Crohn's disease in humans, although its role as a human pathogen has not been entirely accepted. For this reason, management of public health risk due to M. paratuberculosis remains an important policy issue in agri-food public health arenas in many countries. Responsible authorities must decide whether existing mitigation strategies are sufficient to prevent or reduce human exposure to M. paratuberculosis. A Web-based questionnaire was administered to topic specialists to elicit empirical knowledge and opinion on the overall public health impact of M. paratuberculosis, the importance of various routes of human exposure to the pathogen, existing mitigation strategies and the need for future strategies. The questionnaire had four sections and consisted of 20 closed and five open questions. Topic specialists believed that M. paratuberculosis is likely a risk to human health (44.8%) and, given the paucity of available evidence, most frequently ranked it as a moderate public health issue (40.1%). A significant correlation was detected between topic specialists' commitment to M. paratuberculosis in terms of the number of years or proportion of work dedicated to this topic, and the likelihood of an extreme answer (high or low) to the above questions. Topic specialists identified contact with ruminants and dairy products as the most likely routes of exposure for humans. There was consensus on exposure routes for ruminants and what commodities to target in mitigation efforts. Described mandatory programmes mainly focused on culling diseased animals and voluntary on-farm prevention programmes. Despite ongoing difficulties in the identification of subclinical infections in animals, the topic specialists largely agreed that further enhancement of on-farm programmes in affected commodities by the agri-food industry (68.4%) and allocation of resources by governments to monitor the issue (92%) are most appropriate given the current state of evidence.

Factors Affecting Detection of Hepatitis E Virus on Canadian Retail Pork Chops and Pork Livers Assayed Using Real-Time RT-PCR.

We collected 599 Canadian retail pork chops and 283 pork livers routinely (usually weekly) from April 2011 to March 2012 using the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) retail sampling platform. Samples were assayed using validated real-time (q) reverse transcriptase polymerase chain reaction (RT-PCR) and nested classical RT-PCR for the detection of hepatitis E virus (HEV), porcine enteric calicivirus (PEC) and rotavirus (RV). The presence of Escherichia coli, Salmonella spp. and Campylobacter spp. was measured on a subset of our samples. Exact logistic regression models were fitted for predictors for HEV detection, for each assay. For both assays, sample type (pork chop versus liver) was a significant predictor for HEV RNA detection. For nested classical RT-PCR but not qRT-PCR, region of sample collection was a significant predictor (P = 0.008) of HEV detection. Odds of HEV detection were greatest in spring relative to other seasons. E. coli was a significant predictor for HEV RNA detection using the qRT-PCR (P = 0.03). Overall, the prevalence of E. coli, Salmonella spp. and Campylobacter spp. was significantly greater than HEV, PEC or RV on our retail pork samples. Our sparse data set for the detection of PEC and RV precluded modelling of risk factors for the detection of these viruses.

Social and Economic Aspects of the Transmission of Pathogenic Bacteria between Wildlife and Food Animals: A Thematic Analysis of Published Research Knowledge.

Wildlife is a known reservoir of pathogenic bacteria, including Mycobacterium bovis and Brucella spp. Transmission of these pathogens between wildlife and food animals can lead to damaging impacts on the agri-food industry and public health. Several international case studies have highlighted the complex and cross-sectoral challenges involved in preventing and managing these potential transmission risks. The objective of our study was to develop a better understanding of the socio-economic aspects of the transmission of pathogenic bacteria between wildlife and food animals to support more effective and sustainable risk mitigation strategies. We conducted qualitative thematic analysis on a purposive sample of 30/141 articles identified in a complementary scoping review of the literature in this area and identified two key themes. The first related to the framing of this issue as a 'wicked problem' that depends on a complex interaction of social factors and risk perceptions, governance and public policy, and economic implications. The second theme consisted of promising approaches and strategies to prevent and mitigate the potential risks from transmission of pathogenic bacteria between wildlife and food animals. These included participatory, collaborative and multidisciplinary decision-making approaches and the proactive incorporation of credible scientific evidence and local contextual factors into solutions. The integration of these approaches to address 'wicked problems' in this field may assist stakeholders and decision-makers in improving the acceptability and sustainability of future strategies to reduce the transmission of pathogenic bacteria between wildlife and food animals.

A scoping review of the role of wildlife in the transmission of bacterial pathogens and antimicrobial resistance to the food Chain.

Wildlife can contribute to environmental contamination with bacterial pathogens and their transfer to the human food chain. Global usage and frequent misuse of antimicrobials contribute to emergence of new antimicrobial resistant (AMR) strains of foodborne pathogens. We conducted a scoping review of published research to identify and characterize the evidence on wildlife's role in transmission of AMR and/or bacterial pathogens to the food chain. An advisory group (AG) of 13 North American experts from diverse disciplines was surveyed to solicit insight in the review scope, priority topics and research characteristics. A pre-tested search strategy was implemented in seven bibliographic databases (1990 to January 2013). Citations were relevance screened, and key characteristics on priority topics extracted independently by two reviewers. Analysis identified topic areas with solid evidence and main knowledge gaps. North America reported 30% of 866 relevant articles. The prevalence of five targeted bacterial pathogens and/or AMR in any pathogen in wildlife was reported in 582 articles. Transmission risk factors for selected bacteria or AMR in any bacteria were reported in 300. Interventions to control transmission were discussed in 124 articles and formally evaluated in 50. The majority of primary research investigated birds, cervids, rodents, feral pigs, opossums, E. coli (n = 329), Salmonella (n = 293) and Campylobacter (n = 124). An association between wildlife and transmission of bacterial pathogens and/or AMR to the food chain was supported in 122 studies. The scoping review identified a significant body of research on the role of wild birds in the prevalence and transmission of E. coli, Salmonella and Campylobacter. There was little research employing molecular methods contributing to the evidence concerning the importance and direction of transmission of wildlife/pathogen combinations. Given the advancements of these methods, future research should focus in this area to help prioritize future intervention studies and risk mitigation strategies.

Proficiency samples for quality assurance in Trichinella digestion tests.

A reliable method to produce proficiency samples containing known numbers of Trichinella spiralis cysts for use in quality assurance systems for Trichinella digestion tests was developed and validated. A filtrate containing Trichinella cysts was produced by homogenizing and filtering the muscles of an experimentally infected rat. Using a stereomicroscope and micropipette, intact cysts were removed from the filtrate and were transferred onto an agar substrate to allow accurate counting and subsequent transfer into a sample matrix. The proficiency sample matrix consisted of 20-g balls of lean ground beef and was combined with 80 g of a Trichinella-free muscle tissue to obtain the required 100-g sample weight for the assay. The mean overall larval recovery from 404 proficiency samples was 93.0%. Larval recoveries > or = 95, 85, and 75% occurred in 52.4, 84.4, and 94.3%, respectively, of the 404 samples tested. Results indicated that, after a short training period, technicians with no prior experience in digestion techniques performed as well as experienced technicians. The maximum shelf life of proficiency samples was not determined but was at least 3 weeks. Validation data were used to develop panels composed of proficiency samples prepared as described above and to establish guidelines for the interpretation of proficiency panel results.

Experiences and attitudes towards evidence-informed policy-making among research and policy stakeholders in the Canadian agri-food public health sector.

Policy-makers working at the interface of agri-food and public health often deal with complex and cross-cutting issues that have broad health impacts and socio-economic implications. They have a responsibility to ensure that policy-making based on these issues is accountable and informed by the best available scientific evidence. We conducted a qualitative descriptive study of agri-food public health policy-makers and research and policy analysts in Ontario, Canada, to understand their perspectives on how the policy-making process is currently informed by scientific evidence and how to facilitate this process. Five focus groups of 3-7 participants and five-one-to-one interviews were held in 2012 with participants from federal and provincial government departments and industry organizations in the agri-food public health sector. We conducted a thematic analysis of the focus group and interview transcripts to identify overarching themes. Participants indicated that the following six key principles are necessary to enable and demonstrate evidence-informed policy-making (EIPM) in this sector: (i) establish and clarify the policy objectives and context; (ii) support policy-making with credible scientific evidence from different sources; (iii) integrate scientific evidence with other diverse policy inputs (e.g. economics, local applicability and stakeholder interests); (iv) ensure that scientific evidence is communicated by research and policy stakeholders in relevant and user-friendly formats; (V) create and foster interdisciplinary relationships and networks across research and policy communities; and (VI) enhance organizational capacity and individual skills for EIPM. Ongoing and planned efforts in these areas, a supportive culture, and additional education and training in both research and policy realms are important to facilitate evidence-informed policy-making in this sector. Future research should explore these findings further in other countries and contexts.

Antimicrobial use and resistance in aquaculture: findings of a globally administered survey of aquaculture-allied professionals.

There is limited published information regarding antimicrobial use (AMU) and antimicrobial resistance (AMR) in aquaculture. Our objective was to determine the opinions of aquaculture-allied professionals around the world on the frequency of AMU and AMR in common aquatic species. The study questionnaire included five sections: respondent demographics, extent of AMU in aquaculture, frequency of observations of AMR in aquaculture, AMR monitoring and surveillance and antimicrobial susceptibility testing in various jurisdictions. It was administered in English and Spanish to 604 professionals in 25 countries and with varying expertise in aquaculture. The response rate was 33% (199/604). Over half of the participants had >10 years of experience in aquaculture: 70% (140/199) were involved in fish health/clinical work and their primary experience was with salmon, tilapia, trout, shrimp (including prawn) and/or catfish. Tetracycline use was reported by 28%, 46%, 18%, 37% and 9% of respondents working with catfish, salmon, tilapia, trout and shrimp, respectively. Resistance to tetracycline in one or more species of bacteria was reported as 'frequent-to-almost always' for the same aquaculture species by 39%, 28%, 17%, 52% and 36% of respondents, respectively. 'Frequent-to-almost always' use of quinolone was reported by 70% (32/46) and 67% (8/12) of respondents from the United States and Canada, respectively, where quinolone products are not approved for aquaculture, and extra-label fluoroquinolone use is either prohibited (United States) or discouraged (Canada). Similar frequencies of quinolone use were also reported by the majority of respondents from Europe [70% (7/10)] and Asia [90% (9/10)] where labelled indications exist. This baseline information can be used to prioritize research or surveillance for AMU and AMR in aquaculture.

A systematic review-meta-analysis of primary research investigating the effect of selected alternative treatments on gastrointestinal nematodes in sheep under field conditions.

Selected alternative treatments for preventing or controlling gastrointestinal nematodes (GIN) in sheep under field conditions were evaluated using a systematic review-meta-analysis methodology. Forty-three publications reporting 51 studies (21 controlled studies (CS) and 30 challenge studies (ChS)) and 85 unique treatment comparisons were included in the review. The alternative treatment categories were nutraceuticals (28 studies), breeding for genetic resistance (12), nutritional manipulation (6), homeopathies (2), administration of copper oxide wire particles (2), and biological control (1). Random effect meta-analyses (MA) and meta-regression were performed with the natural logarithm of the difference in means (lnMD) between the control and treatment groups, for fecal egg counts per gram of wet feces (FEC), worm counts (WC) or fecal egg counts per gram of dry matter (FECDM) as the outcome. Treatment effect estimates (lnMD) were back-transformed to their count ratios (CR), a relative measure of effect for controlled versus treated groups, for presentation of results. Significant heterogeneity was observed for both CS and ChS that evaluated nutraceuticals, genetic resistance and nutrition treatments. MA of ChS that investigated nutraceuticals resulted in a significant overall CR of 1.62 (P<0.01) and 1.64 (P<0.01) for FEC and FECDM, respectively and a marginal significant CR of 1.14 (P=0.06) for WC, all favoring the treated groups. MA of CS and ChS that investigated genetic resistance resulted in a significant overall CR of 5.89 and 15.42, respectively (P<0.01), again favoring treated groups. MA of CS that investigated homeopathies with FEC as an outcome were homogenous (I(2)=0.0%) and resulted in a non-significant pooled CR of 1.61. ChS investigating copper oxide wire particle treatments and WC as an outcome, were homogenous (I(2)=0.0%) and had a marginally significant pooled CR of 1.68 (P=0.06). Publication bias was observed for ChS with WC outcomes, indicating that small size studies reporting non-significant CR, were less likely to be published than similar studies that found a significant CR. In a meta-regression, randomization (6.2%) and study size (29.2%) were the main factors contributing to the total variation when the outcome was FEC, and none of the variables contributed to between study heterogeneity. When the outcome was WC, type of treatment was the only significant covariate, explaining 6% of the heterogeneity and 38.5% of the total variation. The methodological soundness and reporting of primary research in the selected studies were low. Our results indicate that from the studied alternative treatments, nutraceuticals and use of genetically resistant sheep might be more promising for control of GINs in sheep.

Knowledge and attitudes towards food safety among Canadian dairy producers.

The Canadian dairy industry has recently begun implementing an on-farm food-safety (OFFS) program called Canadian Quality Milk (CQM). For CQM to be effective, producers should be familiar with food-safety hazards in their industry and have an adequate understanding of on-farm good production practices that are necessary to ensure safe food. To assess their knowledge and attitudes towards food safety, a postal questionnaire was administered to all (n=10,474) Canadian dairy producers enrolled in dairy herd-improvement organizations in 2008. The response rate was 20.9% (2185/10,474). Most producers (88.7%) reported that they or their families consume unpasteurized milk from their bulk milk tanks and 36.3% indicated that consumers should be able to purchase unpasteurized milk in Canada. Producers who reported completion of a dairy-health management course (OR=0.74, 95% CI: 0.60, 0.92) and participation in CQM (OR=0.79, 95% CI: 0.64, 0.97) were less likely to support the availability of unpasteurized milk for consumers, while organic producers (OR=2.10, 95% CI: 1.27, 3.47), younger producers (aged <30) and producers with smaller herds were more likely to favour this practice. Two-thirds of producers (66.7%) were concerned that antimicrobial resistance (AMR) might preclude successful treatment of sick cattle. Producers who completed a dairy-health management course (OR=1.37, 95% CI: 1.11, 1.69), organic producers (OR=2.00, 95% CI: 1.09, 3.69) and producers from Quebec compared to each other province were more likely to indicate concern about AMR. Most producers reported that Salmonella (74.2%) and Escherichia coli (73.0%) could be transmitted through contaminated beef or milk to humans, while most were not sure or did not think that Brucella (70.3%) and Cryptosporidium (88.5%) could be transmitted via these routes. Most producers did not perceive that any type of farm visitor has a high risk of introducing infectious agents into their herds. Producers rated veterinarians as very knowledgeable about OFFS (90.9% answered 4 or 5 on a five-point scale) and a favoured (73.1%) source of information about food safety. In contrast, only 13.2% and 30.2% of producers, respectively, indicated that consumers and government personnel are knowledgeable about OFFS. Targeted continuing education for dairy producers in Canada should address the major gaps in knowledge and attitudes towards food safety identified in this study, and veterinarians should be included as key knowledge-transfer informants.

Examining heterogeneity in the diagnostic accuracy of culture and PCR for Salmonella spp. in swine: a systematic review/meta-regression approach.

The accuracy of bacterial culture and PCR for Salmonella in swine was examined through systematic review of existing primary research in this field. A replicable search was conducted in 10 electronic databases. All steps of the review were conducted by two reviewers: to identify relevant publications, to assess their methodological soundness and reporting, and to extract raw data or reported test accuracy estimates. Meta-analyses and meta-regression were performed: to evaluate pooled estimates of test sensitivity (Se) and specificity (Sp), to identify variables explaining the variation in reported test estimates, and to evaluate the association between these variables and reported test Se and Sp. Twenty-nine studies were included in the review. Unique test evaluations reported in these 29 studies were categorized according to the type of test comparison: culture versus culture (n = 134 test evaluations) and PCR versus culture (n = 21). We identified significant heterogeneity among evaluations for each test category. For culture, more heterogeneity was caused by differences in individual test protocols (52%) than overall differences between studies (16%). Enrichment temperature, study population, agar and enrichment type were significantly associated with variation in culture Se. Furthermore, interaction between enrichment temperature and enrichment type was detected. For PCR, most of the heterogeneity was caused by overall differences between studies (65-70%); sample type and study size were associated with variation in reported PCR Se and Sp. The overall methodological soundness and/or reporting of primary studies included in this review were poor, with variable use of reference standards, and consistent lack of the use or reporting of blinding, randomization and subject (sample) selection criteria. Consequently, the food safety and veterinary public health research community should formally consider ways for standardizing the conduct and reporting of this type of research.