Phenotypic and transcriptomic analysis reveals the antibiofilm mechanism of Litsea cubeba essential oil against Bacillus cereus and its application in pork preservation

Bacillus cereus is a common foodborne pathogen that can result in diarrhea and vomiting. It can easily exist in food production environments and form biofilms that are difficult to remove. This study investigated the inhibitory effect and mechanism of Litsea cubeba essential oil (LC-EO) against B. cereus biofilm based on phenotype and transcriptomics, as well as the application in pork preservation. The results showed the MIC and MBIC were 0.125 mg/mL and 0.250 mg/mL, respectively. After LC-EO treatment, the extracellular DNA (eDNA) decreased significantly, the swimming motility was almost completely inhibited. Additionally, LC-EO interferes with AI-2/LuxS QS system by inhibiting key enzyme genes (metC, metK, metQ) in AI-2 signaling molecule synthesis pathway and the key genes (lsrF, lsrK) in the downstream signal transduction pathway. Moreover, molecular docking studies have shown that citral can target five key enzymes (LuxS, metC, metK, LsrF and LsrK). qRT-PCR results also showed that LC-EO significantly inhibited flagellar motility related genes (fla, fliY), QS related genes (codY, SinR, Sin I, plcR) and ten virulence-related genes. Finally, the experiment of LC-EO in pork preservation showed that LC-EO can be used to extend the shelf life of pork.