en تخصصي Special Original article Original article <span style="font-size:14px;"><span style="font-family:times new roman;"><strong>Background: </strong>The increasing demand for natural preservatives results in their extended usefulness. The objective of the present study was to investigate the physicochemical and antioxidative characteristics of <em>Rhus coriaria</em> L. (sumac) fruit and comparison of its antioxidative and antibacterial activity with <em>Zataria multiflora</em> Essential Oil (ZEO) as native Iranian natural additives.<br> <strong>Methods:</strong> Antioxidant activities of<em> Z. multiflora </em>Boiss and sumac were analyzed by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, <em>2, </em>2&#39;-azino-bis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS). Reducing power tests were used for measuring antioxidant activity. Total phenolic content of extract and essential oil were studied as well. The Minimal Inhibitory Concentration (MIC), Minimal Bactericidal Concentration (MBC), and Fractional Inhibitory Concentration (FIC) of a hydroalcoholic extract of sumac and ZEO against of <em>Salmonella </em>Typhimurium and <em>Listeria monocytogenes</em> were studied. Statistical analysis of data was performed using the SPSS software.<br> <strong>Results:</strong> The phenolic content in sumac extract (305.65 mg<span dir="RTL">/</span>g) was significantly (<em>p</em>˂0.05) higher than ZEO (179.42 mg<span dir="RTL">/</span>100 g). The highest level of antibacterial activity was demonstrated by ZEO with the MICs of 0.625 for <em>S. </em>Typhimurium and 1.25 mg/ml for<em> L. monocytogenes</em>.<br> <strong>Conclusion:</strong> Sumac extract showed more potent antioxidative activity than ZEO. However, based on the results of antibacterial activity, ZEO had more potent than sumac extract, significantly.<br> <br> <strong>DOI:</strong> 10.18502/jfqhc.6.1.454</span></span> Rhus, Thymus Plant, Anti-Bacterial Agents, Antioxidants 16 24 http://jfqhc.ssu.ac.ir/browse.php?a_code=A-10-140-3&slc_lang=en&sid=1 A. Mojaddar Langroodi drali_ml2@yahoo.com 0000-0002-7182-6542 Yes Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran H. Tajik No Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran T. Mehdizadeh No Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran