Purpose: This study evaluated the occurrence of L. monocytogenes in the processing environment of a butcher shop, assessed the adhesion potential of obtained isolates, and checked their sensitivity to two sanitizers used during the cleaning in this facility.
Methods: Surface samples were obtained from tables, knives, inside of butcher displays, grinders and meat tenderizers (8 samples per point). All samples were subject to detection of L. monocytogenes according to ISO 11.290-1, and the obtained isolates were characterized by their serogroups and subjected to PCR for detection of virulence genes. Finally, the isolates were evaluated for in vitro adhesion capacity and sensitivity to two sanitizers: A (Mister MaxDG1™) and B (B-Quart Sept™).
Results: Of the total of 40 samples, 75% were positive for Listeria spp. and 22.5% for L. monocytogenes. Twenty isolates were characterized as belonging to serogroup 1/2c or 3c, and showed positive results for all checked virulence genes. All isolates showed some adhesion potential, ranging from weak to moderate, and only one isolate presented a strong adhesion. The evaluated sanitizers had the potential to inhibit the multiplication of isolates, being also able to inhibit adhesion and remove previously formed biofilms. After evaluation, the sanitizers were adopted by the butcher shop in its sanitation routine, and after two months surface samples were collected and none presented positive results for L. monocytogenes.
Significance: The results allowed us to characterize the L. monocytogenes contamination in the butcher shop and to predict their virulence potential. Collected data allowed identification of adhesion potential by L. monocytogenes and the effectiveness of the tested sanitizers to control contamination by this pathogen.