THE INHIBITORY EFFECT OF ESSENTIAL OILS ON THE GROWTH OF GENUS PENICILLIUM ISOLATED FROM PEANUTS BY CONTACT VAPOR

Abstract

The aim of this study was evaluation of the antifungal activity of 5 essential oils (EOs). We used concretely thyme, clove, basil, jasmine and rosemary EOs by vapor contact against the fungal species, namely Penicillium citrinum (P1 – P2), P. crustosum (P3 – P4) and P. expansum (P5 – P6) and their ability to affect production of mycotoxins. Each fungus was inoculated in the center on Czapek Yeast Autolysate Agar (CYA) dishes. Dishes were tightly sealed with parafilm and incubated for fourteen days at 25 ± 1 °C (three replicates were used for each treatment). Volatile phase effect of 50 μl of the essential oils was found to inhibit on growth of Penicillium spp.. Fungicidal and fungistatic concentracions (MFC) were determined by microathmosphere method. Complete growth inhibition of the isolates by EOs of thyme and clove was observed. The most sensitive isolate was P. crustosum (P4) (P < 0.05) The essential oils (EOs) of basil and rosemary had antifungal effect on growth of P. citrinum (P1 – P2) after 3 day of the incubation at concentration 100 % of EOs. The most resistant isolates were P. expansum (P5 – P6). Growth of these isolates was inhibited by thyme and clove EOs (100 %), like each other tested isolates, but with effective MFC concentration of 30 % (30/70; v/v) after all days of cultivation. Data were evaluated statistically by 95.0 % Tukey HSD test. In this stud, we also tested potential effect of EOs to affect production of mycotoxins of tested Penicillium isolates which are potential toxigenic fungi. After 14 days of incubation with EOs (100 %) with control sets, they were screened for a production of mycotoxins by TLC chromatography. Oils exhibited a various spectrum of fungal toxicity inhibit all tested species except the jasmine EO.
The present study demonstrated the potential food preservative ability of the thyme, clove, basil, jasmine and rosemary EOs. The jasmine EO has none antifungal or anti – toxic activity.