Abstract

Antifungal effects of 6 herbal essences (thyme, oregano, spearmint, lime, eucalyptus and galbanum) that seemed to have powerful antifungal characteristics on Aspergillus parasiticus were studied in this research. A. parasiticus is one of the most important species that produces aflatoxin in pistachios. The herbal essences of the used concentrations had no effects on the flavor of pistachios. We used pure lyophilized culture of A. patasiticus for laboratory experiments. After activation of fungus, a suspension containing 10⁶ spore/ml was prepared and cultured in yeast extract sucrose medium, containing different concentrations of essences (between 200 to 1000 ppm). Then, the growth ratio of fungus was determined by weighting produced mycelium. The results were analyzed statistically to determine the most appropriate essence and the minimum inhibitory concentration (MIC) of each one. The results indicated that essences of thyme and oreganohad the most inhibitory effect on A. patasiticus growth at concentrations of 200 and 400 ppm, respectively.

Key words: Aflatoxin, antifungal, Aspergillus parasiticus, essence, pistachio.