Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 4 1 2012 03 15 30 34 M Raeisi Department of Food Quality Control, Faculty of Veterinary Medicine, Urmia university, Urmia, Iran. H Tajik Department of Food Quality Control, Faculty of Veterinary Medicine, Urmia university, Urmia, Iran Roohani SM Razavi Department of Food Quality Control, Faculty of Veterinary Medicine, Urmia university, Urmia, Iran. M Maham Department of Clinical Sciences, Faculty of Veterinary Medicine, Urmia university,Urmia, Iran. M Moradi Department of Food Science and Technology, Ahar Faculty of Agriculture, University of Tabriz, Tabriz, Iran. B Hajimohammadi Department of Food Hygiene and Safety, Faculty of Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran H Naghili Department of Food Quality Control, Faculty of Veterinary Medicine, Urmia university, Urmia, Iran. M Hashemi Department of Food Quality Control, Faculty of Veterinary Medicine, Urmia university, Urmia, Iran. T Mehdizadeh Department of Food Quality Control, Faculty of Veterinary Medicine, Urmia university, Urmia, Iran. 2015 10 16 Background and Objectives: In this study, the antibacterial effect of essential oil of tarragon (Artemisia dracunculus) on Staphylococcus aureus and Escherichia coli was evaluated in culture media and Iranian white cheese. Materials and Methods: The tarragon essential oil (EO) obtained by the steam distillation method and its antibacterial activity was evaluated in 96-well microtiter plates containing brain heart infusion broth. The enumeration of S. aureus and E. coli in cheese samples were carried out on the following media: Baired parker agar for S.aureus, incubated at 37 °C for 24 h; and MacConkey sorbitol agar for E. coli, incubated at 37°C for 24 h. Iranian white cheese was produced from fresh and whole pasteurized cow milk (2.5%). Bacteria (103 cfu/mL) were inoculated to different batches. Cheese was treated with different concentrations of EO (15 and 1500 µg/mL) and separated into four parts in an equal manner. The sensory evaluation was done by a panel of four judges. Results: According to the results obtained, minimum inhibitory concentrations (MIC) for E. coli and S. aureus were 2500 and 1250 µg/mL, respectively. Also, minimum bactericidal concentration (MBC) for the mentioned microorganisms were 5000 and 2500 µg/mL, respectively. All the EO concentrations for each bacteria result in reducing bacterial count of cheese samples compared to control (P < 0.05). Also, with increasing concentration of EO in cheese samples, the bacterial count was reduced further (P < 0.05). Conclusion: Based on our findings, tarragon essential oil has antibacterial effect on two important pathogen bacteria (S. aureus and E. coli) and can be applied as a preservative in foods such as cheese. https://ijm.tums.ac.ir/index.php/ijm/article/view/716 https://ijm.tums.ac.ir/index.php/ijm/article/download/716/483