Enhanced sanitation standard operating procedures have limited impact on Listeria monocytogenes prevalence in retail delis

In a recent longitudinal surveillance study in 30 US retail delicatessens, 9.7% of environmental surfaces were positive for Listeria monocytogenes, and we found substantial evidence of persistence. In this study, we aimed to reduce the prevalence and persistence of L. monocytogenes in the retail deli environment by developing and implementing practical and feasible intervention strategies (ie, sanitation standard operating procedures; SSOPs). These SSOPs were standardized across the 30 delis enrolled in this study. SSOP implementation was verified by systems inherent to each retailer. Each deli also was equipped with ATP monitoring systems to verify effective sanitation. We evaluated intervention strategy efficacy by testing 28 food and nonfood contact surfaces for L. monocytogenes for 6 months in all 30 retail delis. The efficacy of the intervention on the …