Combined antibacterial effect of Origanum compactum and Mentha piperita (Lamiaceae) essential oils against ATCC Escherichia coli and Staphylococcus aureus

With the increasing concerns about the safety of chemical synthetic substances being added to food products, companies are beginning to search for natural sources of antimicrobials. Because essential oils were proven to have antimicrobial properties, they can be used as food preservatives. The mixture of essential oils may have a more potent antimicrobial profile compared to any single essential oil. Hence, the purpose of this work was to determine the chemical composition and inhibitory effects of Origanum compactum L. and Mentha piperita L. (Lamiaceae) essential oils alone or in combination against Staphylococcus aureus ATCC 29,213 and Escherichia coli ATCC 25,922. It is the first time reporting a combination of these two essential oils to control foodborne pathogens type Escherichia coli and Staphylococcus aureus. The major constituents of O. compactum essential oil were determined as carvacrol, thymol, p-cymene, and ?-terpinene. Regarding M. piperita essential oil, menthofuran, menthol, methyl acetate, 1,8 cineole, and ?-pinene were the major compounds. The mixture of essential oils presented a strong synergistic effect against E. coli, decreasing the minimum inhibitory concentration (MIC) of O. compactum from 0.0625% to 0.015625% (v/v) and the MIC of M. piperita from 1% to 0.125% (v/v). It was concluded that a mixture of essential oils provides a better antimicrobial effect against tested bacteria than that of the essential oils alone. © 2021, Society for Plant Research.