Exploring the occurrence of in biofilms and deciphering the bacterial community in a frozen vegetable producing environment.

The establishment of within food processing environments constitutes a significant public health concern. This versatile bacterium demonstrates an exceptional capacity to endure challenging environmental conditions in the food processing environment, where contamination of food products regularly occurs. The diverse repertoire of stress resistance genes, the potential to colonize biofilms, and the support of a co-existing microbiota have been proposed as root causes for the survival of in food processing environments. In this study, 71 sites were sampled after cleaning and disinfection in a European frozen vegetable processing facility, where in-house clones persisted for years. and were detected by a culture-dependent method at 14 sampling sites, primarily on conveyor belts and associated parts. The presence of biofilms, as determined by the quantification of bacterial load and the analysis of extracellular matrix components (carbohydrates, proteins, extracellular DNA) was confirmed at nine sites (12.7%). In two cases, was detected in a biofilm. Furthermore, we explored the resident microbial community in the processing environment and on biofilm-positive sites, as well as the co-occurrence of bacterial taxa with by 16S rRNA gene sequencing. , , and dominated the microbial community of the processing environment. Using differential abundance analysis, amplicon sequence variants (ASVs) assigned to Enterobacterales (, , unclassified ) and were found to be significantly higher abundant in -positive samples. Several ASVs were less abundant in -positive compared to -negative samples. , , , and were key players in the microbial community in biofilms, and and were more relatively abundant in biofilms. Further, the microbial composition varied between the different areas and the surface materials.