The Role of Nisin, Monolaurin, and EDTA in Antibacterial Effect of Rosmarinus Officinalis L. and Cinnamomum Zeylanicum Blume Essential Oils on Foodborne Pathogens

Abstract

In this study, the role of nisin, monolaurin and EDTA in strengthening antibacterial effect of the Rosmarinus officinalis L. and Cinnamomum zeylanicum Blume essential oils were tested against foodborne pathogens including Escherichia coli, Salmonella typhimurium, Listeria monocytogenes and Staphylococcus aureus. The essential oils extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (CG-MS). For determining antimicrobial effects of the essential oils in corporation with nisin, monolaurin and EDTA, agar disk diffusion and broth micro dilution susceptibility tests were used. According to GC-MS analyses, 15 and 14 components were identified for rosemary and cinnamon essential oils that representing 95.1 % and 94.25 % of total components, respectively. In the case of rosemary essential oil, 1,8-cineole (24.3 %), α-pinene (22.8 %), and camphor (12.1 %) were determined as the main volatiles. On the other hand, cinnamaldehyde (79.74 %) was determined as the major compound for cinnamon essential oil. According to antimicrobial activity tests, L. monocytogenes was found as the most sensitive microorganism. It is followed by S. aureus, E. coli, and S. typhimurium, respectively. In general, EDTA made the weakest effect on the MIC and MBC values of the essential oils. On the other hand, nisin made the most promising effect on the MIC and MBC values of the essential oils. In conclusion, using monolaurin, nisin and EDTA together with essential oils led to increases the antibacterial effect of essential oils against both Gram positive and Gram negative tested bacteria.