Quantitative microbial exposure assessment of uropathogenic Escherichia coli in ready-to-eat chicken: Consumer risk and mitigation strategies in Taiwan.

Poultry is a significant reservoir of uropathogenic Escherichia coli (UPEC), an emerging foodborne pathogen linked to urinary tract infections. Ready-to-eat (RTE) meats, often consumed without reheating, are vulnerable to contamination during the retail stage. This is the first study in Taiwan to quantitatively assess consumer exposure to UPEC from RTE chicken while identifying feasible risk mitigation strategies. We developed a retail-to-fork quantitative microbial exposure assessment (QMEA) to evaluate UPEC risks in RTE chicken and propose evidence-based food safety interventions. In total, 96 RTE meats were purchased, including chicken (n = 21), pork (n = 25), beef (n = 20), and duck (n = 30), from wet markets, supermarkets, and caterers in Taiwan. Escherichia coli enumeration was performed using plate count methods, while UPEC strains were identified via PCR targeting UPEC-specific genes (c3509, c3686, and chuA). Monte Carlo simulations (with 10,000 iterations) were performed to estimate exposure probabilities exceeding critical thresholds (105-108 CFU/g per serving). Model parameters included UPEC prevalence and concentration, bacterial growth during retail-to-consumption stages, time-temperature conditions, and consumer serving sizes. A sensitivity analysis was performed to identify the input variables with the greatest impact on exposure risk, and intervention scenarios, such as modifying retail practices and improving storage conditions, were evaluated for their effectiveness in reducing UPEC risks. Among all sampled RTE meats, UPEC prevalence was highest in RTE chicken (7/21, 33.3 %), compared with pork (5/25, 20.0 %), beef (2/20, 10.0 %, and duck (2/30, 6.7 %). The model estimated a 4.0 % probability of high UPEC exposure (>8 log CFU/serving) from wet markets and 1.1 % from caterers. The UPEC concentration at retail, retail duration, and retail storage temperature were the most influential risk factors. Shortening retail time to within 2 h and maintaining storage temperatures of 18 °C reduced exposure risk by 0.98-0.99 times. These findings emphasize the need for targeted interventions to mitigate UPEC contamination. This study presents a novel framework for understanding UPEC risks in RTE chicken in Taiwan and highlights practical strategies to enhance food safety through improved retail and consumption practices.