Co-Occurrence of L. monocytogenes with Other Bacterial Genera and Bacterial Diversity on Cleaned Conveyor Surfaces in a Swine Slaughterhouse

Bacterial pathogens, such as Listeria monocytogenes, can show resistance to disinfection and persistence on working surfaces, permitting them to survive and contaminate food products. Persistence—a complex phenomenon involving interactions between many bacteria within a biofilm—is modulated by in situ characteristics. This study aimed to describe, in silico, the microbiota identified in a swine slaughterhouse after sanitation procedures to better understand the presence of L. monocytogenes on these surfaces. Molecular tools for characterization of microbial communities were used to assess the relative contribution of different bacteria resulting from this phenomenon, and the 16S rRNA sequencing method was used on samples from meat conveyor belt surfaces collected on four sampling visits to study the co-occurrence between L. monocytogenes and other bacteria. From the background microbiota, a total of six genera were found to be negatively correlated with Listeria spp., suggesting Listeria growth inhibition, competition, or at least an absence of shared habitats. Based on these results, a complete scenario of interactions of Listeria with components of background microbiota was established. This work contributes to identifying avenues that could prevent the growth and persistence of L. monocytogenes on food-processing surfaces.