Investigating the presence of environmental Listeria in butcher shop utensils and surfaces using Petrifilms

Foodborne illnesses persist as a substantial global public health threat, with Listeria monocytogenes being especially alarming due to its high fatality rate and ability to survive in food-processing settings. Both conventional (culture-based) and molecular techniques were employed in this study to investigate the incidence of environmental Listeria spp. in butcher shops in Mosul, Iraq. Eighty swab samples were collected from knives, hooks, cutting boards, and refrigerator inner surfaces across 20 butcher shops. Using 3M™ Petrifilm™ plates, 24% of the samples showed signs of presumptive Listeria spp. The API Listeria system showed different biochemical reactions during verification, and PCR amplification of the iap gene confirmed L. monocytogenes in 15% of the total samples. Knives and hooks had the highest contamination rate, with 37% and 26% of positive detections, respectively. Cutting boards had 21%, and refrigerator surfaces had 16%. The results showed how everyday utensils can lead to cross-contamination and highlighted L. monocytogenes as a continuing public health risk in stores that sell meat. The phylogenetic analysis showed that the Mosul isolate (PX204934) clustered closely with the Baghdad isolates (MN960572 and MN960575), indicating a common regional lineage. Improved sanitation, regular monitoring, and proper staff training are important to reduce environmental contamination and prevent L. monocytogenes from entering the food chain.