Effective Inhibition of Listeria monocytogenes Biofilm Formation by Satureja rechingeri Essential Oil: Mechanisms and Implications

Abstract

Biofilm formation by foodborne pathogens, particularly Listeria monocytogenes, poses a significant challenge in food industry facilities. In this study, we investigated the inhibitory potential of Satureja rechingeri essential oil (Sr-EO) against L. monocytogenes growth and biofilm formation. Gas chromatography-mass spectrometry analysis revealed a high carvacrol content in Sr-EO, a compound with known antimicrobial properties. We examined the effects of Sr-EO on initial attachment and preformed biofilms, using crystal violet and MTT assays to quantify attached biomass and metabolic activity, respectively. Our results demonstrated that Sr-EO not only prevented initial attachment but also effectively disrupted preformed biofilms, indicating its potential as a biofilm-control agent. Microscopy analysis revealed alterations in bacterial cell membranes upon Sr-EO treatment, leading to increased permeability and cell death. Additionally, Sr-EO significantly suppressed bacterial motility, with concentrations exceeding 0.25 μL/mL completely inhibiting motility. Furthermore, gene expression analysis revealed the down regulation of genes associated with biofilm formation, attachment, and quorum sensing, suggesting that Sr-EO modulates bacterial gene transcription. These findings suggest that Sr-EO can be a promising candidate for controlling biofilm formation and bacterial contamination in food processing environments.