The effect of extracts of four Iranian pistachio cultivars (Pistacia vera) on the growth rate of Aspergillus flavus and the production of aflatoxin B1

Pistacia vera L. pistachio is considered one of the most important export items of Iran, which can be a suitable substrate for the growth of toxin-producing fungi and, as a result, the production of aflatoxin B. The purpose of this study is to investigate the effects of four pistachio cultivars including Akbari, Ahmad Aghaei, Kalh-Qouchi from Damghan City, and Badami sefid from Faizabad City as well as the oleic, linoleic, palmitic and stearic fatty acids contained in it on the growth of Aspergillus flavus and reducing the amount of aflatoxin B1. In the present research, pistachio extract was prepared with a rotary machine under vacuum and analyzed with a GC-MS machine. Antifungal effects of extracts and fatty acids were investigated separately by disc diffusion methods, minimum inhibitory concentration, minimum fungicidal concentration, and the level of aflatoxin B1 by HPLC. The highest amount of oleic fatty acid with 66.3% was found in Akbari pistachios. Among the most effective extracts and fatty acids on the investigated fungi, Pistachio Akbari and Ahmed Aghaei with MIC equal to 10 µg/ml and MFC equal to 200 and 250 µg/ml respectively, and oleic fatty acid with MIC and MFC equal to 15 and 250 µg/ml. In the combination of four pistachio extracts with four fatty acids, the highest reduction in aflatoxin production was observed with 36.77 μg/kg, compared to the control sample (843.95 μg/kg). Therefore, fatty acids in pistachios can be used as a biocompatible preservative without affecting the taste of pistachios.