en Food Safety and Hygiene Food Safety and Hygiene پژوهشي Original Article <div class="WordSection1"><span style="line-height:1;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="page:WordSection1"><b>Background:</b> The present study aimed to determine the chemical composition and antibacterial activity of essential oil extracted from <i>Ziziphora clinopodioide</i> (ZCEO) <i>in vitro</i>. Furthermore, the study aimed to evaluate the effectiveness of chitosan nanoemulsion coating containing ZCEO and nisin in inhibiting the growth of <i>Listeria monocytogenes</i> inoculated on chicken breast fillets that were inoculated and vacuum-packaged, and stored at a temperature of 4&plusmn;1 &deg;C for 16 days.<br> <b>Methods:</b> The chemical composition and <i>in vitro </i>antibacterial activity of ZCEO were determined by gas chromatography-mass spectrometry (GC-MS) and microdilution method, respectively. The chicken breast fillet samples were divided into seven groups, namely, the control group (uncoated) without vacuum, control group with vacuum, chitosan nanoemulsion without vacuum, chitosan nanoemulsion with vacuum, chitosan nanoemulsion with 0.5% ZCEO and vacuum, chitosan nanoemulsion with nisin and vacuum, and chitosan nanoemulsion with 0.5% ZCEO, nisin, and vacuum. All the samples were stored in a refrigerator, and the population of <i>L.</i> <i>monocytogenes</i> was enumerated on days 0, 1, 2, 4, 8, 12, and 16.<br> <b>Results: </b>the chemical analysis of ZCEO revealed that carvacrol, thymol, and p-cymene were the three main compounds present in the oil. Application of chitosan nanoemulsion coatings, specifically chitosan nanoemulsion + ZCEO 0.5% + vacuum and chitosan nanoemulsion + nisin + vacuum, resulted in a significant reduction in the growth rate of <i>L.</i> <i>monocytogenes</i> in chicken<b> </b>breast fillet samples during storage. In addition, the chitosan nanoemulsion coating containing the combined ZCEO and nisin was found to be more effective in reducing the growth of <i>L.</i> <i>monocytogenes</i> during the storage period.<b> </b><br> <span style="page-break-after:avoid"><b>Conclusion: </b>Based on the results of this study, chitosan nanoemulsion + ZCEO 0.5% + nisin + vacuum coating can be used to reduce the risks that might be associated with <i>L. monocytogenes</i><i> </i>in chicken breast fillets<span style="color:black">.</span></span></span></span></span></span></div> <div aria-label="Page Break" class="cke_pagebreak" contenteditable="false" data-cke-display-name="pagebreak" data-cke-pagebreak="1" style="page-break-after:always" title="Page Break"></div> Chitosan nanoemulsion, Ziziphora clinopodioide, Nisin, Listeria monocytogenes, Chicken meat, 100 105 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-582-1&slc_lang=en&sid=1 Vahid Behmanesh behmanesh_v@outlook.com 100319475328460012927 0009-0004-2771-9901 No Department of Food Hygiene and Aquaculture, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran. Saeid Khanzadi khanzadi@um.ac.ir 100319475328460012928 100319475328460012928 Yes Department of Food Hygiene and Aquaculture, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran. Mohammad Hashemi hashemimd@mums.ac.ir 100319475328460012929 100319475328460012929 No Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Medical Toxicology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. Mohammad Azizzadeh m-azizzadeh@um.ac.ir 100319475328460012930 100319475328460012930 No Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran. Fatemeh Mollaei f.mollaei@hotmail.com 100319475328460012931 0009-0002-1353-5744 No Department of Food Hygiene and Aquaculture, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.