Unraveling the inhibitory mechanism of clove essential oil against Listeria monocytogenes biofilm and applying it to vegetable surfaces

Listeria monocytogenes (L. monocytogenes) can adhere to biological or non-biological surfaces, including food processing equipment and storage containers. Subsequently, they can contaminate food by forming a biofilm, thereby causing serious food safety problems. In this project, the natural antibacterial agent clove essential oil (CEO) was selected to control L. monocytogenes biofilm, and the effect and mechanism of its action on the biofilm were explored in depth. TEM and CLSM observation results showed that CEO can destroy the dense membrane structure of the biofilm, thereby acting on the released free bacteria. Meanwhile, the study found that after CEO (2 Minimum biofilm inhibition concentration) treatment, the metabolic activity of the bacteria was reduced by 60.26%, and the secretion of extracellular polysaccharides and proteins was significantly inhibited. Besides, the CEO treatment can down-regulate the expression levels of the genes agrA, agrC, agrD, and prfA and up-regulate the expression level of the gene sigB, thereby regulating the formation of biofilms. Finally, CEO showed a significant removal effect on biofilms on different materials and vegetable surfaces.