Antimicrobial activity of essential oils of Origanum vulgare L. and Origanum majorana L. against Staphylococcus aureus isolated from poultry meat

One of the microorganisms present in poultry meat products responsible for the most usual foodborne intoxication is Staphylococcus aureus. Essential oil of spices has been used as a bio-preservative due to its antimicrobial activity against foodborne pathogens. The aim of this study was to evaluate the antimicrobial activity in vitro of the essential oils of oregano and marjoram against S. aureus isolated from poultry meat marketed in Pelotas/RS-Brazil, and to carry out the phenotypic and molecular characterization of these oils. For this, twenty samples of poultry meat were analyzed. Staphylococcus spp. was isolated from Baird Parker agar, and its molecular characterization was performed by PCR. All isolates of S. aureus were tested for the presence of genes coding for staphylococcal enterotoxins. Antimicrobial activity of essential oils of oregano and marjoram was evaluated by disk diffusion, minimal inhibitory concentration and minimal bactericidal concentration. The results showed that seventeen samples were contaminated by Staphylococcus positive-coagulase and nine were positive to acriflavine resistance and thermonuclease tests, and in the last ones S. aureus was confirmed. The genes coding for staphylococcal enterotoxins detected were sea (6) and seb (3). All isolates were sensitive to essential oils tested, indicating that these can be an alternative to food preservation. (C) 2015 Elsevier B.V. All rights reserved.