Quantitative risk assessment of human salmonellosis associated with Canadian broiler chicken breast

The aim of this thesis was to estimate risk of human salmonellosis due to consumption of broiler chicken breasts in Canadian homes and to assess the effectiveness of different risk mitigation strategies on the predicted risk. A comprehensive review of chicken production and product movement within Canada and literature available to estimate risk of human salmonellosis from chicken was summarized. The focus was on the pathway from retail-to-consumption at private homes. The review identified Canadian research data along this pathway and highlighted important data gaps. Recommendations for future research, which can be used to allocate resources to priority areas to be able to conduct a complete Canadian risk assessment were made.;A QRA model using Codex Alimentarius components - hazard identification, hazard characterization, exposure assessment, and risk characterization - was conducted to predict the overall risk of human salmonellosis due to consumption of contaminated chicken breasts in Canadian homes. The model described the growth, inactivation, and transfer of Salmonella on chicken breast from the time it leaves Canadian retail establishments until it is consumed, with special consideration of handling and cooking practices. The expected risk per serving was estimated to be 3.27 x 10-4 (95% CI from 0.00 to 0.082) or 1700 cases per 100,000 per year. Sensitivity analysis was conducted to study the effect of different risk mitigation strategies on the predicted risk of human salmonellosis. Concentration of Salmonella on chicken breasts at retail, hand and cutting board washing after handling raw chicken, and proper cooking were identified as the most critical parameters in reducing risk of human salmonellosis. This model emphasizes that food safety responsibility is a shared responsibility among all handlers of chicken breasts.;A quantitative comparison of growth and inactivation of Salmonella in chicken meat versus laboratory media using meta-analysis was conducted for the first time. Significant difference in growth and inactivation between the two martices was found. Alternatively, growth and inactivation equations in chicken using mixed effect models were developed to be used as inputs in future quantitative risk assessment (QRA) models that estimate the number of Salmonella under different treatment conditions. Recommendations for improving the quality of reporting and designing of experimental trials in the food safety literature related to Salmonella growth/inactivation in chicken were noted.