Essential oils mixtures as inhibitors of Listeria monocytogenes, a Food-Borne bacterium

Five essential oils obtained from common plants from the Ecuadorian Highlands were tested as inhibitors of Listeria monocytogenes. Oregano (Oreganum vulgare; Lamiaceae), laurel (Laurus nobilis; Lauraceae) and lemongrass (Cimbopogon citratus; Poaceae) yielded antibacterial essential oils, whose MIC was ranged from 25 to 12.5 μl/ml. Mixture design was used as a strategy to enhance the antilisterial activity displayed by the bioactive essential oils. Mixtures of the three bioactive oils were prepared according to a simplex-lattice design. The binary mixture composed by oregano and laurel oil showed a better activity, compared with the pure components (6.25 μl/ml). The bioactive mixture was applied as food preserver in the preparation of two ready-to-eat products. The shelf-life of the meat products was up to 60 days. Besides, the flavor, odor and appearance of the evaluated products had a good acceptance by a non-trained taster panel.