Deciphering the potential risks of Yersinia enterocolitica across multi-points in food chain: prevalence, biofilm, and cross-stage transmission routes.

Yersinia enterocolitica, a major foodborne zoonotic pathogen with the capabilities of biofilm formation and psychrotolerance, poses critical risks to food transportation and cold-chain safety. This study investigated its prevalence, distribution, and biofilm traits across diverse food products and associated environments, and cross-stage transmission routes of this pathogen were inferred through single nucleotide polymorphism (SNP) and multi-locus sequence typing (MLST) based analysis. A total of 1550 food and 670 environmental samples were analyzed, yielding 402 and 160 isolates, with the overall prevalence rate of 25.9 % and 23.9 %, respectively. Elevated positive rates were detected in raw livestock (40.4 %) and poultry (37.0 %) meat, with meat-based quick-frozen products (72.0 %) and frozen duck meat (66.7 %) demonstrating the highest prevalence. Environmental samples revealed distinct spatial patterns, with slaughterhouses (40.2 %) and farmers' markets (34.8 %) as high-risk zones compared to household kitchens (6.4 %). Biofilm analysis of 562 isolates highlighted source-dependent differences, and 77.8 % (437/562) isolates formed biofilms, with 30.3 % (122/402) food-derived isolates lacking this trait versus only 1.9 % (3/160) environment-derived isolates. Moreover, a gradient increase of strong and extremely strong biofilm-forming isolates was observed along raw meat production, processing, retail, and consumption chain, with 20.5 % (16/78) of slaughterhouses, 31.7 % (20/63) of farmers' markets, and 36.8 % (7/19) of household kitchens. Phylogenetic integration of SNP and MLST data identified five dominant sequence types (STs) including ST3, ST563, ST157, ST536, ST338 associated with slaughterhouses, and farmers' markets, designating these sites as critical hotspots for persistence contamination. These STs exhibited relatively strong biofilm-forming abilities (81.1 % moderate to strong, and one strain extremely strong), underscoring their role in establishing persistent reservoirs, and thereby driving sustained contamination. Together, our novel findings highlights specific genetic and functional traits of Y. enterocolitica associated with cross-stage transmission risk, providing actionable insights for targeted mitigation in food safety management.