A quantitative microbial risk assessment of Escherichia coli O157:H7 in sheep meat in Saudi Arabia

Background Escherichia coli O157:H7 is an important foodborne pathogen associated with severe clinical outcomes. It has been detected in sheep and sheep meat in Saudi Arabia. However, quantitative estimates of exposure and illness risk under the Saudi food-supply context remain limited. Methods A probabilistic quantitative microbial risk assessment model was developed for sheep meat. Seven fixed initial contamination levels were evaluated, ranging from −3 to 3 log 10 CFU/g. Each level was simulated under two storage scenarios: recommended refrigeration (1–5 °C) and a plausible temperature distribution. Saudi consumption and supply patterns were maintained across scenarios. Results Across the seven contamination levels, both the probability of illness and modeled annual incidence increased with initial concentration. At 3 log 10 CFU/g, the median probability of illness was 1.50 × 10 −9 under recommended storage and 3.40 × 10 −9 under plausible storage. Median annual incidence was zero cases per 100,000 under both scenarios when rounded to the nearest whole case. Factor-fixing sensitivity analysis identified the probability of illness from a single organism as the most influential parameter, followed by internal cooking temperature. Conclusion The modeled results suggest that population-level risk is associated with a subset of high-exposure scenarios observed within the simulation. Variation across storage and cooking conditions is reflected in the distribution of outcomes.