Study on Some of Pistachio Cultivars’ Contamination of Khorasan-e-Razavi Province to Aspergillus flavus

In order to study on some of pistachio cultivars’ contamination of Khorasan-e-Razavi province,eight cultivars of pistachio kernels were collected from the pistachio production areas of this province. Using serial dilution method, 10 grams of ground pistachio was moved to 90 ml water peptone and continuous dilutions 10-1, 10-2 were prepared. Then 0.1 ml from each dilution was inoculated in three replicates on plates containing AFPA medium and was placed inside an incubator at 28 ° C for 72 hours. The characteristic of this environment is the advent of green yellowish colonies by Aspergillus flavus and Parasiticus that is distinguishing criteria of mentioned fungi. Since it has capacity to stop interfering bacteria and fungi growth causes the emersion of distinct and discrete colonies that are easily seperable and countable from each other. After three days, the number of colonies of A.flavus was identified and calculated in samples. The results of this research indicated that there was a significant difference in colonies number of these fungi in different pistachio cultivars (At 5% level). Among these cultivars Akbari Namavar had the highest contamination and against, Fandoghi 1 had the lowest contamination