Assessment of Listeria monocytogenes cross-contamination from enoki mushrooms to ready-to-eat foods in commercial hot pot settings

This study assessed the cross-contamination dynamics of Listeria monocytogenes from enoki mushrooms to ready-to-eat (RTE) foods in commercial hot pot settings. Transfer rate quantification and exposure assessment were used to evaluate contamination risks during consumption and storage. High transfer efficiencies were observed during the consumption phase, with 78.11% from enoki to wooden chopsticks and 67.99% from chopsticks to crispy meat. In contrast, transfer to refrigerator surfaces (7.79%-15.04%) and vegetable surfaces (1.19%, and not detected) during storage was limited. Exposure assessments estimated a maximum L. monocytogenes concentration of 5.33 log CFU/g in enoki mushrooms after transportation and storage. The estimated cross-contamination during consumption (0.030 log CFU/g; crispy meat via enoki-contaminated chopsticks) was significantly higher than that during storage (0.001 log CFU/g; lettuce via enoki). These findings revealed that wooden chopsticks served as a critical vector for L. monocytogenes in hot pot consumption, exceeding the risks associated with refrigeration. Sensitivity analysis identified the initial L. monocytogenes load in enoki mushrooms as the primary determinant of cross-contamination risk, followed by transportation temperature, transfer probability, and transfer rate. Therefore, mitigating foodborne listeriosis requires strict control of the initial bacterial load in enoki mushrooms and enhanced sanitation protocols for utensils in commercial settings.