The biosynthetic machinery of bacterial cell walls has been the most target site by antimicrobial
compounds [23,24]. EOs and their derivatives can act against both cell walls (including membranes) and
cytoplasm, often completely changing the morphology of the cells. Because of these properties, EOs are
regarded as potential alternatives to antibiotics in animal production systems [25–27]. EOs increase the
permeability of bacterial cell membranes resulting in cell contents leakage and eventually killing the
cell. The leakage usually occurs through cell wall degradation, cytoplasmic membrane damage,
cytoplasm coagulation and membrane proteins destruction [28–31] as well as the proton motive force
reduction [32], where the EOs could play a decidedly active role.