AUTHOR=Zwirzitz Benjamin , Wetzels Stefanie U. , Dixon Emmanuel D. , Fleischmann Svenja , Selberherr Evelyne , Thalguter Sarah , Quijada Narciso M. , Dzieciol Monika , Wagner Martin , Stessl Beatrix 

TITLE=Co-Occurrence of Listeria spp. and Spoilage Associated Microbiota During Meat Processing Due to Cross-Contamination Events

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.632935

DOI=10.3389/fmicb.2021.632935

ISSN=1664-302X

ABSTRACT=<p>A large part of foodborne outbreaks related to <italic>Listeria monocytogenes</italic> are linked to meat and meat products. Especially, recontamination of meat products and deli-meat during slicing, packaging, and repackaging is in the focus of food authorities. In that regard, <italic>L. monocytogenes</italic> persistence in multi-species biofilms is one major issue, since they survive elaborate cleaning and disinfection measures. Here, we analyzed the microbial community structure throughout a meat processing facility using a combination of high-throughput full-length 16S ribosomal RNA (rRNA) gene sequencing and traditional microbiological methods. Samples were taken at different stages during meat cutting as well as from multiple sites throughout the facility environment to capture the product and the environmental associated microbiota co-occurring with <italic>Listeria</italic> spp. and <italic>L. monocytogenes</italic>. The listeria testing revealed a widely disseminated contamination (50%; 88 of 176 samples were positive for <italic>Listeria</italic> spp. and 13.6%; 24 of 176 samples were positive for <italic>L. monocytogenes</italic>). The pulsed-field gel electrophoresis (PFGE) typing evidenced 14 heterogeneous <italic>L. monocytogenes</italic> profiles with PCR-serogroup 1/2a, 3a as most dominant. PFGE type MA3-17 contributed to the resilient microbiota of the facility environment and was related to environmental persistence. The core in-house microbiota consisted mainly of the genera <italic>Acinetobacter</italic>, <italic>Pseudomonas</italic>, <italic>Psychrobacter</italic> (<italic>Proteobacteria</italic>), <italic>Anaerobacillus</italic>, <italic>Bacillus</italic> (<italic>Firmicutes</italic>), and <italic>Chryseobacterium</italic> (<italic>Bacteroidota</italic>). While the overall microbial community structure clearly differed between product and environmental samples, we were able to discern correlation patterns regarding the presence/absence of <italic>Listeria</italic> spp. in both sample groups. Specifically, our longitudinal analysis revealed association of <italic>Listeria</italic> spp. with known biofilm-producing <italic>Pseudomonas</italic>, <italic>Acinetobacter</italic>, and <italic>Janthinobacterium</italic> species on the meat samples. Similar patterns were also observed on the surface, indicating dispersal of microorganisms from this multispecies biofilm. Our data provided a better understanding of the built environment microbiome in the meat processing context and promoted more effective options for targeted disinfection in the analyzed facility.</p>