Tehran University of Medical Sciences Journal of Food Safety and Hygiene 2476-3241 4 3/4 2019 06 30 168 168 Samira Vaziri Department of Biology, Payame Noor University, Tehran, Iran Siavash Hamzeh pour Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mosayeb Dalvand Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 2019 02 04 2019 04 22 Due to the increased resistance to antibiotics, identifying new compounds with fewer side effects is more important than usual medications in treatment of microorganisms. This study aimed to examine the antibacterial activity of Zataria multiflora, Rosemarinus officinalis and Cuminum cyminum essential oils on the growth of E. coli O157:H7 as one of the most common pathogens of food-borne diseases. Z. multiflora, R. officinalis and C. cyminum plants were dried and ground. Then the extraction of essential oil was performed by the hydrodistillation method. In order to examine the antibacterial effects, micro-broth dilution was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC). The disc diffusion method was applied to measure the inhibitory zone diameter. The data were analyzed by SPSS. Maximum diameter of inhibition zone (26.96 mm) was related to Z. multiflora which had a significant difference compared to other essential oils (p<0.001). Also the MIC and MBC of Z. multiflora essential oil were obtained as 3.125 mg/ml and 6.25 mg/ml, respectively. In this study, Zataria multiflora, Rosemarinus officinalis and Cuminum cyminum essential oils had significant antibacterial properties against E.coli O157:H7. As a result of these essential oils after completing studies, they can be a good alternative to chemical preservatives for storage of food. https://jfsh.tums.ac.ir/index.php/jfsh/article/view/168 https://jfsh.tums.ac.ir/index.php/jfsh/article/download/168/96