Seydim and Sarikus (2006) stated that the use of 2% (w/v) OEO was required for whey protein isolate (WPI) films to reach the minimum inhibitory concentration against S. aureus,S. enteritidis, L. monocytogenes, Lactobacillus plantarum, and E. coliO157:H7. The antibacterial effect has been mainly attributed to oregano’s terpenoid fraction comprised of carvacrol, thymol, and p-cymene (Corrales et al., 2014). It was expressed that carvacrol forms channels through the bacterial membrane by pushing apart the fatty acid chains of the phospholipids, allowing ions to leave the cytoplasm (Burt, 2004). Representative pictures of the inhibitory effect of biocomposite films incorporated with 1.2% (w/v) OEO against four test microorganisms in comparison with the control are shown in Fig. 6.