Table 3 shows the antibacterial effects of CMC edible films incorporated with ZEO at different concentrations, against five Gram-positive or Gram-negative bacteria.The results showed ZEO’s significant inhibitory effects on bothGram-positive and Gram-negative bacteria (Table 3); these effectsincreased with increasing ZEO concentration. The control (with-out ZEO) film did not show an inhibition halo around the film disc;ZEO3 had the largest inhibition zone against all tested bacteria. Var-ious mechanisms have been suggested for the antibacterial effectof essential oils, such as their attacking the phospholipid bilayer ofthe cell membrane or disrupting enzyme systems, the productionof fatty acid hydroperoxidase, the coagulation of cytoplasm, dam-age to lipids and proteins, disturbance of the proton motive force,and the genetic material of bacteria being compromised [49–51].The first of these has been reported to be a main antimicrobialmechanism due to the lipophilic nature of essential oils, whichenables them to act on the cell membrane, causes important mor-phological damages, disrupts membrane integrity, and depletes thecell’s contents. These results are in agreement with the findingsof some studies that showed that carvacrol and thymol signifi-cantly disrupted the cell membranes disruption of some bacteria,such as Escherichia coli O157 H7, Listeria monocytogenes, and S.Typhimurium [52–55]. Gram-negative bacteria were more resistantthan Gram-positive bacteria. This might be attributed to their outermembrane being impermeable to lipophilic compounds such as