Use of an ecosystem-based approach to shed light on the heterogeneity of the contamination pattern of Listeria monocytogenes on conveyor belt surfaces in a swine slaughterhouse in the province of Quebec, Canada

The role of the accompanying microbiota in the presence of Listeria monocytogenes on meat processing surfaces is not yet understood, especially in industrial production conditions. In this study, 300 conveyor belt samples of the cutting room of a swine slaughterhouse were collected during production. The samples were subjected to the detection of L. monocytogenes and strains representative of the spatial and temporal diversities were compared with core genome multi-locus sequence typing analysis. The sequencing of the V4 region of the 16S RNA gene of the microorganisms harvested from each sample was carried out using the Illumina MiSeq platform. Diversity analyses were performed and MaAsLin analysis was used to assess the link between L. monocytogenes detection and the surrounding bacteria. The 72 isolates collected showed a low genetic diversity and important persistence characteristics. L monocytogenes isolates were not stochastically distributed on the surfaces: the isolates were detected on three out of six production lines, each associated with a specific meat cut: the half carcasses, the bostons and the picnics. The MaSLin 1 analysis identified the taxa Veillonella as a bacterial determinant of the presence of L. monocytogenes on processing surfaces. The results of this study revealed a heterogenous contamination pattern of the processing surfaces by L. monocytogenes and targeted a bacterial indicator of the presence of the pathogen. Those results could lead to a better risk assessment of the contamination of meat products.