Targeted biofilm inhibition and gene expression to study the synergistic antibacterial mechanism of lauric acid and citral against Listeria monocytogenes

Contamination by Listeria monocytogenes poses significant food safety concerns. Prior research has demonstrated that lauric acid (LA) and citral, compounds present in Litsea cubeba fruit, exhibited synergistic antibacterial effects against L. monocytogenes , although the precise mechanisms remain inadequately understood. Consequently, this study investigated the synergistic mechanism of LA and citral against L. monocytogenes , focusing on biofilm inhibition and gene expression effects. The results indicated that treatment with Synergism LA + citral significantly reduced the intracellular DNA content of L. monocytogenes . The antibacterial combination inhibited biofilm formation by altering bacterial surface hydrophobicity, self-aggregation, and motility, while also disrupting mature biofilms and eradicating internal bacteria. Significant changes were observed in genes associated with multiple pathways related to metabolism and quorum sensing in L. monocytogenes . Additionally, the Synergism LA + citral effectively inhibited L. monocytogenes in pasteurized refrigerated milk while maintaining stable milk brightness and pH. These findings enrich the synergistic antibacterial mechanism of LA and citral and provide promising evidence for their antibacterial application in food products.