Mojtaba Raeisi - Department of Public Health, Faculty of Health, Golestan University of Medical Sciences, Gorgan, Iran
Hossein Tajik - Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
Seyed Mehdi Razavi Rohani - Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
Bektas Tepe - Department of Molecular Biology and Genetics, Faculty of Science and Literature, Kilis ۷ Aralik University, Kilis, Turkey
Hossein Kiani - Bioprocessing and Biodetection Laboratory, Department of Food Science, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran
Rahem Khoshbakht - Department of Food Hygiene and Public Health, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran
Hesamaddin Shirzad Aski - Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
Hamed Tadrisi - Graduated of Veterinary Medicine, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

Listeria monocytogenes is one of the major causes of infections in developing countries. In this study, chemical composition and anti-listerial effect of the essential oil of Zataria multiflora Boiss. alone and in combination with monolaurin were evaluated at different pH values (۵, ۶, and ۷) and temperatures (۵ ˚C and ۳۰ ˚C). Chemical composition of Zataria multiflora Boiss. essential oil was evaluated by gas chromatography-mass spectrometry (GC-MS) analysis. Minimum inhibitory concentration (MIC) of the essential oil and monolaurin were determined using microbroth dilution method and the interactions of essential oil and monolaurinwere determined by the evaluation of fractional inhibitory concentrations (FIC) index.Carvacrol (۶۳.۲۰%) and thymol (۱۵.۱۰%) were found as the main components of the essential oil. The MIC values of the oil and monolaurin at pH ۷ and ۳۰ ˚C were measured as ۳۱۲.۵۰ µg mL-۱ and ۱۲۵.۰۰ µg mL-۱, respectively. Combination of monolaurin and Z. multiflora essential oil were found to act synergistically (FIC index < ۰.۵) against L. monocytogenes under different pH and temperature conditions. Decrease in the pH and temperature values have increased the anti-listerial activity of monolaurin and the essential oil. The lowest MIC value of monolaurin and essential oil was observed at pH ۵ and ۵ ˚C. According to our results, the oil alone or in combination with monolaurin at low pH and temperature conditions showed a promising inhibitory effect on L. monocytogenes.

essential oil, Listeria monocytogenes, Minimum inhibitory concentration, Monolaurin, Zataria multiflora Boiss