en Food Science Food Science پژوهشي Research <strong>Background and Objectives: </strong>In this study, antibacterial effects of whey protein coating with <em>Mentha aquatica L</em>. essential oil on <em>Escherichia coli</em>, <em>Enterobacter</em> and <em>Klebsiella pneumoniae</em> in Iranian white cheese were investigated.<br> <strong>Materials and Methods: </strong><em>Mentha aquatica </em>L. essential oil was extracted using Clevenger apparatus.<em> Mentha aquatica </em>L. essential oil was added to each whey protein coating solution at 0.5, 1 and 1.5% concentrations. Whey protein treatment included cheese, bacteria and whey protein with no <em>Mentha aquatica </em>L. essential oil. Control treatment only included cheese and bacteria with no <em>Mentha aquatica </em>L. essential oil and whey protein. Minimal inhibitory concentration and minimal bactericidal concentration were assessed for the bacterial species. Antibacterial properties of the designed active coating system against <em>Escherichia</em><em> coli</em>, <em>Enterobacter </em>and <em>Klebsiella pneumoniae</em> were assessed using direct cell counting and disk diffusion methods.<br> <strong>Results: </strong><em>Mentha aquatica L</em>. essential oil at 1.5% concentration at the end of Day 15 of storage at 4 &deg;C inhibited growth of <em>Escherichia coli</em>, <em>Enterobacter</em> and <em>Klebsiella</em> <em>pneumoniae</em> up to 100, 64 and 18%, respectively. To achieve the highest growth inhibition of <em>Escherichia coli</em>, <em>Enterobacter</em> and <em>Klebsiella</em><em> pneumoniae</em>, 1.5, 1 and 1% of the essential oil were used to preserve organoleptic properties of the cheese.<br> <strong>Conclusions: </strong>Use of whey protein coating with 1.5% essential oil included no adverse effects on organoleptic, sensory and appearance characteristics of the cheese. Whey protein coating with <em>Mentha aquatica L</em>. essential oil inhibited growths of <em>Escherichia coli</em> completely and <em>Enterobacter</em> partially in Iranian white cheese. Biopolymer coating, Enterobacter, Escherichia coli, Essential oils, Food protection, Dairy products, Klebsiella pneumonia 49 58 http://nfsr.sbmu.ac.ir/browse.php?a_code=A-10-922-1&slc_lang=en&sid=1 Sajedeh Rezaiee s.rezaiee@yahoo.com 10031947532846005221 10031947532846005221 No Department of Chemical Engineering, Shahrood Branch, Islamic Azad University, Shahrood, Iran Fatemeh Ardestani ardestani_fatemeh@yahoo.com 10031947532846005222 10031947532846005222 Yes Department of Chemical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran Morteza Khoshvaght m.khosvaght@gmail.com 10031947532846005223 10031947532846005223 No Department of Chemical Engineering, Shahrood Branch, Islamic Azad University, Shahrood, Iran