Abstract Aims: This study aimed to in v estigate the effect of Oliveria decumbens essential oil ( Od- EO) on the phenotypic properties and gene expression of Staphylococcus aureus biofilm on commonly used food contact surfaces. Methods and results: The minimum inhibitory concentration and minimum bactericidal concentration of Od-EO on S . aureus ATCC25923 were determined to be 0.5 and 1 μl/ml, respectiv ely. Cry st al violet st aining , scanning electron microscopy (SEM), biofilm met abolic activit y e v aluation, and real-time PCR analysis were used to assess the anti-biofilm properties of Od- EO. The results demonstrated that Od- EO exhibited significant anti-biofilm properties against S. aureus and effectively reduced the metabolic activity of biofilm cells. Furthermore, the inhibitory effects of Od- EO on biofilm formation were more pronounced on stainless steel (SS) compared to high-density poly eth ylene (HDPE) surf aces. R eal-time PCR analy sis re v ealed that Od- EO do wnregulated the e xpression of biofilm-related genes ( icaA , icaD , clfA , clfB , FnbA , FnbB , and hld ) in S. aureus grown on SS, while the expression levels of all studied genes except hld in the biofilm formed on HDPE remained unchanged or increased. Conclusions: One of the main anti-biofilm mechanisms of the Od-EO on the HDPE is related to the disturbance in the QS of the cells. These findings highlight the potential of Od- EO as an effective agent for controlling and inhibiting S. aureus biofilm in the food industry and its potential use in disinfectant compounds.
