Effect of Zataria multiflora Boiss. essential oil and starter culture on Staphylococcus aureus and Listeria monocytogenes during the manufacture, ripening, and storage of white brined cheese

Different concentrations of Zataria multiflora Boiss. essential oil (EO: 0, 50, 150 and 300 ppm), starter culture (ST: 0, and 5 mu L mL(-1)), and storage times (up to 60 days) were used in a factorial design study to evaluate their effects on growth of Staphylococcus aureus and Listeria monocytogenes during manufacturing, ripening, and storage of Iranian white brined cheese. In addition to the fortunate resistance of starter culture to EO, the growth of these pathogens was affected significantly (P < 0.01) by EO concentrations >= 50 ppm, ST, and their combinations. Therefore, a synergistic inhibitory effect between EO and ST was observed. Furthermore, according to ELISA assays EO can prevent the enterotoxin production by Staph. aureus during cheese manufacturing, ripening and storage even at its lowest concentration (50 ppm). These results suggest EO and ST can play an important role as food preservatives.