Structured Co-Contamination Patterns of Foodborne Pathogens Across Raw Foods: Implications from a Decade-Long Public...

Globally, zoonotic bacterial pathogens like Salmonella spp. and pathogenic Escherichia coli remain leading causes of foodborne illness. While raw materials are critical exposure interfaces, long-term evidence regarding multi-pathogen co-contamination across food matrices is limited. We conducted a decade-long surveillance study (2016-2025) in South Korea, analyzing 4653 raw food samples-including livestock, agricultural, and marine products-for 12 zoonotic pathogens. Co-contamination was a structured, frequent feature, observed in 16.0% of livestock, 15.8% of agricultural, and 5.6% of seafood samples. Within livestock, chicken exhibited the highest co-contamination rate (27.4%), while pork showed the lowest (3.7%). Matrix-specific pathogen combinations predominated: pathogenic E. coli plus Clostridium perfringens in livestock; C. perfringens plus Bacillus cereus in agricultural products; and Vibrio parahaemolyticus plus V. vulnificus in marine products. Notably, enteropathogenic E. coli (EPEC) constituted 75.0% of pathogenic E. coli in poultry, whereas cattle showed diverse profiles including enterohemorrhagic (EHEC), enterotoxigenic (ETEC), and EPEC. Statistical analysis (Pearson's chi-square or Fisher's exact test) revealed no significant seasonal variation in contamination or co-contamination rates (all p > 0.56), suggesting that stable processing and handling factors exert more influence than climatic drivers. By conceptualizing multi-pathogen co-contamination as a reproducible feature of food systems rather than an incidental event, this study provides critical epidemiological insights into polymicrobial exposure. These findings support the transition toward multi-hazard, pattern-based surveillance and integrated risk-management strategies to enhance zoonotic foodborne disease prevention in public health systems.