Benzalkonium chloride is a quaternary ammonium compound with bactericidal activity, which is widely used in domestic and healthcare settings as well as in food processing environments. It plays an important role in the prevention and control of foodborne pathogens. However, the presence of biofilms or improper use of benzalkonium chloride may enable foodborne pathogens to adapt to bactericides, affecting the tolerance to homologous or heterologous biocidal agents. The review summarizes the relationship between the adaptation of foodborne pathogens to benzalkonium chloride and their tolerance to this biocide. The reasons for the increased tolerance to benzalkonium chloride are explained from the perspectives of the expression of efflux pump genes, cell membrane modification, and the formation of the viable but non-cultivable (VBNC) state. Furthermore, the influence of benzalkonium chloride adaptation on the antibiotic resistance of foodborne pathogens is discussed, and the reasons for the increased antibiotic resistance are summarized from the perspectives of biofilm formation, spontaneous mutations, horizontal gene transfer, and the role of efflux pumps in antibiotic resistance. This review could help understand the mechanism of the adaption of foodborne pathogens to benzalkonium chloride and provide a reference for the rational use of biocides and the prevention and control of foodborne pathogens.

Biofilms, which are microbial communities that adhere to biological or abiotic surfaces, significantly enhance the survival capacity of foodborne pathogens. Biofilms not only effectively block the penetration of antibiotics through physical barriers but also increase the tolerance of pathogens to antibiotics by regulating gene expression and promoting material exchange. Furthermore, biofilms often enhance the pathogenicity of pathogens by upregulating the expression of virulence genes. In addition, the quorum sensing system and cyclic dinucleotide signaling pathway in biofilms play key roles in regulating antibiotic resistance and virulence. Non-coding small RNAs are crucial for maintaining biofilm stability and stress resistance. These mechanisms work in synergy to improve the survival of foodborne pathogens under adverse environmental conditions. Therefore, understanding the influence and mechanism of biofilm formation on antibiotic resistance and virulence in foodborne pathogens is essential for developing safe and effective control strategies. This review focuses on the changes in antibiotic resistance and virulence in foodborne pathogens after biofilm formation and explores the molecular and cellular mechanisms through which biofilms affect resistance and virulence. It aims to provide insights into the risks associated with foodborne pathogen biofilms, offer theoretical support for biofilm-related hazard control in the food processing industry, and provide a scientific basis for developing new antimicrobial strategies and improving food safety management practices.