The effects of Heracleum platytaenium Boiss essential oil on the growth of ochratoxigenic Penicillium verrucosum (D-99756) isolated from Kashar Cheese

Abstract

The antifungal effects of essential oil isolated from Heracleum platytaenium Boiss on the growth of ochratoxigenic Penicillium verrucosum (D-99756) isolated from Kashar cheese were investigated. Minimal inhibitory concentration (MIC) and Minimal lethal concentration (MLC) tests were performed by using broth dilution method. Controls were prepared with three groups; with pure essential oils (Eo) (positive control), methanol and without Eos. The serial doubling dilution of oil was prepared in methanol with concentrations ranging from 500 to 31 mu L/mL. Applied incubation periods were 25 C for 10 days for MIC and 48 hours at the same temperature for MLC. After the incubation period, the tubes were controlled for either mycelia growth or turbidity and sediments. The maximal inhibitory dilution (the minimal inhibitory concentration), exhibiting any growth, was regarded as MIC. Tubes containing Penicillium verrucosum which did not display any growth were subcultured to determine if the inhibition was reversible or permanent. The Eo dilution, which is the not visible growth of typical P. verrucosum colonies on the plates, was accepted as lethal effect. MLC was the lowest concentration of antifungal to completely inhibit fungal growth. The MIC and MFC values were determined as 31 and 125 mu L/mL, respectively.