The Development of a Risk Assessment Model for Inedible Rendering Plants in Canada: Identifying and Selecting Feed Safety-Related Factors.

The Canadian Food Inspection Agency (CFIA) is developing an establishment-based risk assessment model to categorize rendering plants that produce livestock feed ingredients (ERA-Renderer model) according to animal and human health risks (i.e., feed safety risks) and help in determining the allocation of inspection resources based on risk. The aim of the present study was to identify and select feed-safety-related factors and assessment criteria for inclusion in the ERA-Renderer model. First, a literature review was performed to identify evidence-based factors that impact the feed safety risk of livestock feed during its rendering processes. Secondly, a refinement process was applied to retain only those that met the inclusion conditions, such as data availability, lack of ambiguity, and measurability. Finally, an expert panel helped in selecting factors and assessment criteria based on their knowledge and experience in the rendering industry. A final list of 32 factors was developed, of which 4 pertained to the inherent risk of a rendering plant, 8 were related to risk mitigation strategies, and 20 referred to the regulatory compliance of a rendering plant. A total of 179 criteria were defined to assess factors based on practices in the Canadian rendering industry. The results of this study will be used in the next step of the model development to estimate the relative risks of the assessment criteria considering their impact on feed safety. Once implemented, the CFIA's ERA-Renderer model will provide an evidence-based, standardized, and transparent approach to help manage the feed safety risks in Canada's rendering sector.

Expert Elicitation To Estimate the Feed Safety Impact of Criteria Included in the Canadian Food Inspection Agency Risk Assessment Model for Feed Mills.

ABSTRACT: 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.

Source attribution at the food sub-product level for the development of the Canadian Food Inspection Agency 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.

SalmoFresh™ effectiveness in controlling Salmonella on romaine lettuce, mung bean sprouts and seeds.

The purpose of this study was to determine the effectiveness of a commercial Salmonella bacteriophage mixture (SalmoFresh™ 6-phage strains) and to compare its effectiveness with a chlorinated water treatment to reduce Salmonella on produce and seeds at different temperatures and storage times. Two sets of experiments were designed to test phage and chlorinated water effectiveness on produce at 2, 10 and 25 °C at different storage times (1, 24, 48 and 72 h). First, SalmoFresh™ was applied to the surface of lettuce, mung bean sprouts and mung bean seeds that were spot-inoculated with a five Salmonella strain mixture (Newport, Braenderup, Typhimurium, Kentucky, and Heidelberg, 105 CFU/mL) by spraying phages onto lettuce (n = 48 pieces, 3×3 cm2 per treatment) and sprouts (n = 48 pieces per treatment). A second set of experiments (scaled-up) consisted in the application of phages by immersion to Salmonella adulterated lettuce (600 g), 300 g sprouts (300 g) or mung bean seeds (30 g) in a phage cocktail (108 PFU/mL) for 15 min (lettuce and sprouts) or 1 h (seeds). Another group of samples was washed with chlorinated water and yet another group was treated with a combination of chlorinated water followed by phage cocktail. Each experiment was repeated three times by quadruplicates. After the treatments for spot-inoculated and scaled-up experiments, lettuce and sprouts were separated into different lots (10 g/lot) and stored at 2, 10 and 25 °C; Salmonella was enumerated after 1, 24, 48 and 72 h. Adulterated phage-treated seeds were packaged and stored dry at 25 °C. Salmonella was enumerated after 72 h of storage. Groups of phage treated mung bean seeds (720 g) were germinated, and the reduction in Salmonella determined. Results of microplate virulence assays indicated that SalmoFresh™ reduced (P = 0.007) Salmonella by an average of 5.34 logs CFU/mL after 5 h at 25 °C. Spraying SalmoFresh™ onto lettuce and sprouts reduced Salmonella by 0.76 and 0.83 log10 CFU/g, respectively (P < 0.01). Immersion of produce in a phage solution was better at killing Salmonella P < 0.05) than spraying it onto the surface, reducing Salmonella by 2.43 and 2.16 log10 CFU/g on lettuce and sprouts, respectively. SalmoFresh™ was an effective biocontrol intervention to reduce Salmonella on lettuce and sprouts. On seeds, although a reduction was observed, Salmonella was able to grow exponentially during germination; therefore, the phage cocktail was not effective on mung bean seeds or sprouts obtained from adulterated seeds. The combination of hurdles, chlorination fallowed by the phage cocktail was the most effective treatment to reduce Salmonella on lettuce and sprouts.

Selection of risk factors to be included in the Canadian Food Inspection Agency risk assessment inspection model for food establishments.

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.

Ability of Shiga toxigenic Escherichia coli to survive within dry-surface biofilms and transfer to fresh lettuce.

Biofilms are known to play important roles in bacterial survival and persistence in food-processing environments. This study aimed to determine the ability of the top 7 STEC serotypes to form biofilms on polystyrene (POL) and stainless steel (SS) plates and to quantify their survival and transfer from dry-surface biofilms to lettuce pieces. The ability of 14 STEC strains to form biofilms on these two materials at different exposure times and temperatures was assessed using crystal violet, Congo red and SEM. At 10 °C all serotypes were weak biofilm producers on both surfaces. In contrast, serotypes O45-040, O45-445, O103-102, O103-670 and O157-R508 were strong biofilm producers at 25 °C. Strains O103-102, O103-670, O111-CFS, O111-053 and O157:H7-R508 were expressers of curli. Under scanning electron microscopy, strains O103-670, O111-CFS, O157-R508, and O121-083 formed more discernible multilayer, mature biofilms on SS coupons. Regardless of the surface (POL/SS), all STEC strains were able to transfer viable cells onto fresh lettuce within a short contact time (2 min) to varying degrees (up to 6.35 log cfu/g). On POL, viable cell of almost all serotypes exhibited decreased detachment (p = 0.001) over 6 days; while after 30 days on SS, serotypes O45-040, O103-102, O103-670, O111-053, O111-CFS, O121-083, O145-231 O157:H7-R508 and O157:H7-122 were transferred to lettuce. After enrichment, all 14 STEC strains were recovered from dry-surface biofilms on POL and SS plates after 30 days. Results demonstrated that the top 7 STEC remained viable within dry-surface biofilms for at least 30 days, transferring to lettuce within 2 min of exposure and acting as a source of adulteration.