Quantitative Microbial Risk Assessment of Listeriosis Associated With Ready-to-Eat Products in Iran: A Comprehensive Analysis.

A Quantitative Microbial Risk Assessment (QMRA) model was developed to predict the risk of listeriosis associated with consuming ready-to-eat (RTE) products in Iran. Utilizing Monte Carlo simulation software, 79 positive cases were identified out of 2608 samples, yielding an overall prevalence of 58.5%. Prevalence varied across categories (1.01%-6.74%), with Listeria monocytogenes levels below the 100 CFU g-1 threshold in positive samples. The 5th and 95th percentiles for annual listeriosis risk per serving were estimated for vulnerable (6.05 × 10-8 to 1.16 × 10-7) and general populations (1.36 × 10-9 to 2.59 × 10-9). The chicken Turkish kebab ranked highest in the 99th percentile for both subpopulations. Model projections included a 99th percentile estimate of 40 annual listeriosis cases, predominantly in the vulnerable population. Chicken Turkish kebab, chicken kebab, restaurant salad, traditional cheese, and RTE raw vegetables had the highest predicted cases. Sensitivity analyses emphasized the impact of serving size, prevalence, and specific product type on illness probability. The QMRA highlighted a significant listeriosis risk from contaminated RTE products, particularly for vulnerable populations. Validation through Kolmogorov-Smirnov and Anderson-Darling tests confirmed the statistical significance (p > 0.05) of the bootstrapped model's fit.