Evaluation of Antibacterial Effects of Mentha spicata L., Cuminum cyminum L. and Mentha longifolia L. Essential Oils Individually and in Combination with Sodium Benzoate Against Escherichia coli O157:H7 and Listeria monocytogenes

Side effects of chemical preservatives and drug resistance have raised interests in the use of natural preservatives derived from plants. The aim of this study was to examine possible antibacterial effects of Mentha spicata L., Cuminum cyminum L. and Mentha longifolia L. essential oils (EOs) individually and in combination with sodium benzoate against Escherichia coli O157:H7 and Listeria monocytogenes. In this experimental study, the EOs were obtained and analyzed by gas chromatography mass spectrometry. Disc diffusion and broth microdilution methods were used for in vitro antibacterial screening in triplicate. Data analysis was performed by the SPSS software using ANOVA and independent sample t-test. Statistical analysis showed a significant difference between different antibacterial effects of EOs individually and in combination with sodium benzoate. Considering the individual effects of these factors, the antibacterial effect of sodium benzoate and Cuminum cyminum essential oil were the highest against E. coli O157:H7 and L. monocytogenes, respectively. These results are relatively consistent with the disc diffusion test. The antibacterial effects of sodium benzoate in combination with EOs showed significant differences in comparison to sodium benzoate effect individually in most situations (P < 0.05). The results indicated that these EOs have a good antibacterial activity and combined with sodium benzoate could reduce the use of sodium benzoate as a chemical preservative in food, cosmetic, and drug products, which can decrease the possible side effects of it.