•Carvacrol acetate was identified as the major compound of oregano essential oil.•Oregano essential oil presented antioxidant activity by the DPPH and ABTS methods.•Antimicrobial activity of essential oil was effective against A. acidoterrestris.•The use of this essential oil can be indicated as a natural preservative. The Alicyclobacillus spp., causing deterioration in citrus beverages, has been frequently related to the use of natural antimicrobial agents in its combat; in this sense, the study sought to evaluate the activity of the essential oil of oregano (Origanum vulgare) against different isolates of this bacterium, in addition to its antioxidant activities. The minimum inhibitory concentration obtained from oregano essential oil for A. Acidiphilus and A. cycloheptanicus was 125 μg/mL; and for A. herbarius and A. acidoterrestris was 62.5 μg/mL. While the minimum bactericidal concentration obtained was 1000 μg / mL for all isolates. The combined effect of nisin and O. vulgare against A. acidoterrestris resulted in indifference. The antioxidant activity obtained was 363 μmol trolox/mg by the DPPH method and 1142 μmol trolox/mg by the ABTS method. The chemical characterization of the essential oil of oregano by GC–MS was able to identify of 93.13% of the compounds was carried out, where the major compound was carvacrol acetate represented by 59.61%. Further scanning electron microscopy was able to demonstrate damage to cells treated with the inhibitory concentrations of O. vulgare.