The objective this stud was to evaluate the antimicrobial activity of essential oils (organic vs. conventional) of Origanum vulgare L. in the action against Candida albicans, Escherichia coli and Staphylococcus aureus. The inoculation of rhizobacteria (environmental (ME) and Bacillus subtilis) potentiated the antimicrobial action.  The essential oils of Traditional (organic) cultivation presented antibacterial action and antifungal, while the essential oil of conventional cultivation (NPK) showed no any antibacterial or antifungal activity. It was concluded that the formulation of vermicomposting and the use of rhizobacteria are potential technologies and tools for family farmers and traditional community in the cultivation of orégano.

Different combinations of essential oils from cinnamon, cloves, oregano, and thyme were evaluated in vitro for their bactericidal activity against enterotoxigenic Escherichia coli (ETEC). The solutions containing cinnamon (0.03%), oregano (0.16%), and thyme (0.08%) (P1); and clove (0.08%), oregano (0.33%), and thyme (0.04%) (P2), exhibited high bactericidal activity, and were selected for use as preservatives in ground beef inoculated with ETEC and refrigerated. The two preservative solutions (P1 and P2) exhibited significant bactericidal action (p < 0.05) on ETEC, with ETEC reductions of 1.03 and of 0.87 LogUFC/g in the beef samples treated with P1 and P2, respectively. GC-MS analysis of the oil mixtures showed both preservatives to contain significant concentrations of carvacrol. Chromatic degradation was not observed in the samples treated with preservatives. Essential oil mixtures thus concocted are therefore potential preservative candidates in ground beef, as they are capable of controlling ETEC contamination while preserving the products' coloration.