Research progress on the composition and formation mechanism of Salmonella biofilm

Salmonella， as an important foodborne pathogen， was demonstrated to have its pathogenic capacity closely associated with biofilm. Biofilm was recognized as a self-protective structure formed by Salmonella under external stress， which was composed of dense extracellular matrix enveloping bacterial cells， and its formation was regulated by multiple factors. Its life cycle was described as consisting of four main stages： adhesion， aggregation， maturation and dispersal. Biofilm was found to impede the penetration of conventional antibiotics， leading to a markedly reduced susceptibility of Salmonella to antibiotics. Moreover， the extracellular matrix was shown to serve as a platform for the transfer of antimicrobial resistance genes， thereby exacerbating bacterial resistance. In the food industry， biofilm was observed to effectively block the contact of disinfectants with bacterial cells， making it difficult to completely eliminate bacterial colonies attached to equipment， thus serving as a persistent source of contamination and posing risks to consumer health and safety. Current prevention and control measures were focused on disrupting biofilm synthesis， including but not limited to ultrasound， pulsed light， ultraviolet radiation， bacteriophages， disinfectants and engineered materials. The composition and formation mechanisms of Salmonella biofilm were systematically summarized， with the aim of providing a reference for achieving effective control of biofilm and eliminating the food safety risks posed by it， as well as enabling the potential future functional transformation of Salmonella biofilm.