a survey on contamination of iranian pistachio cultivars to aspergillus section flavi and aflatoxin

Population density of aspergillus section flavi in pistachio kernels of iranian cultivars was studied in main pistachio growing areas of iran during 2015 to 2017. in order to investigate the rate of contamination of pistachio cultivars to aspergillus section flavi and aflatoxins, 13 pistachio cultivars, including akbari, kaleh-ghouchi, ovhadi, ahmad-aghaee, momtaz, italian pistachio, shahpasand, pesteh-e-ghermes, pesteh-e-garmeh, ghazvini, abbasali and khanjari were selected from different parts of semnan, khorosan razavi and kerman provinces. a total of 125 samples of pistachio kernels were collected from different cultivars of pistachio trees in orchards. the samples were cultured on afpa using serial dilution method. after 3 to 7 days, the plates were examined and isolates of aspergillus section flavi were identified and relative densities of them were recorded. the values ranged from 1.6×10^3 to 1.6×10^4 cfu/g in pistachio samples.the statistical analysis showed that the population density of aspergillus section flavi was varied with the type of cultivars. the results indicated that among tested cultivars, akbari showed the least and shahpasand the most population density of aspergillus section flavi among pistachio cultivars, respectively. the aflatoxins content of pistachio samples were extracted and analysed through thin layer chromatography (tlc) and flurodensitometer. there were significant differences among different cultivars in the contamination of pistachio kernels to aspergillus section flavi and aflatoxin. (α =5%). it was observed that akbari had the least whereas shahpasand had the greatest amount of aflatoxin production, respectively.