Paparella A, Serio A, Chiarini M, Tettamanti E, Electronic paramagnetic resonance investigation of the activity of Origanum vulgare L. essential oil on the Listeria monocytogenes membrane. Lett Appl Microbiol. 2010 Aug;51(2):149-57

To evaluate the effect of oregano essential oil on Listeria monocytogenes cytoplasmic membrane. Nitroxide free-radical Electron Paramagnetic Resonance was applied on L. monocytogenes after 30 min exposure to oregano essential oil concentrations ranging from 0 to 1.25%. The impact of essential oil on the number of viable cells was evaluated by plate count. The combined approach including microbiological and EPR analyses provided relevant information on membrane modification and cell response to essential oils.