Effects of thyme and rosemary essential oils on the growth of two aflatoxigenic Aspergillus flavus strains

In this study, antifungal effects of thyme (Thymus vulgaris L.) and rosemary (Rosmarinus officinalis L.) essential oils (EOs) on two aflatoxigenic Aspergillus flavus strains (MAM-200682 and MAM-2006113) previously isolated from hazelnut were investigated. Five different concentration of the EOs (500, 250, 125, 62 and 31 mu L/mL) were prepared in methanol. Minimal inhibitory concentration (MIC) values of the thyme and rosemary EOs against two cultures were determined as 31 and 125 mu L/mL, respectively. 250 mu L/mL of thyme EO on A. flavus MAM-200682, and 125 mu L/mL of thyme EO and 500 mu L/mL of rosemary EO on A. flavus MAM-2006113 had fungicidal effect. Fungal growth was almost completely inhibited after 90 min application of thyme EO concentrations (250 and 125 mu L/mL). Rosemary EO caused slight growth inhibition. Thyme EO has the most fungistatic and fungicidal effect against aflatoxigenic A. flavus strains. These results indicated that the thyme and rosemary EOs could be used as natural antimicrobial agents against aflatoxigenic A. flavus in the food preservation practices.