Individual and Synergistic Antimicrobial Effects of Nisin, Resveratrol, Naringenin, and Saponins Against <i>Salmonella</i> Typhimurium Biofilms

This study investigates the individual and synergistic antibacterial and antibiofilm effects of nisin, resveratrol, naringenin, and saponins against <i>Salmonella enterica</i> subsp. <i>enterica</i> serovar Typhimurium ATCC 14028, aiming to identify safe and effective natural combinations to combat bacterial persistence in food processing environments. Through broth microdilution, checkerboard synergy testing, and biofilm/motility assays, alongside molecular docking and qPCR analysis, the research evaluates the antimicrobial efficacy and mechanisms of these compounds. The results highlight that the combination of resveratrol and naringenin exhibits the strongest synergistic activity, effectively inhibiting bacterial growth and biofilm formation. Molecular analyses reveal that this combination targets key proteins, such as BcsA and CsgD, and significantly downregulates genes responsible for biofilm formation, quorum sensing, and motility, suggesting it is a promising natural strategy for controlling <i>Salmonella</i>.