The effects of gamma irradiation on microbial quality and sensory characteristic of four pistachio cultivars during nine months of storage at Kerman

Aflatoxin contamination is one of the main problems for producers, and when compared with other farm produce, pistachio has the highest risk of aflatoxin contamination. In Iran, the maximum acceptable levels of aflatoxin B1 and total aflatoxin are 8 and 10 ppb or nanograms per grams respectively. One way to prevent this dangerous poison is to provide a situation in which there is no possibility for aflatoxin generator fungi to grow. To this end, four aflatoxin-free pistachio cultivars, grown in Kerman, were taken from the Institute of Standards and Industrial Research of Iran. Following the impregnation with the Aspergillus flavus and Aspergillus parasiticus fungal spores were packed and gamma irradiated in 3, 5, and 9-kilo gray doses at the Atomic Energy Organization of Iran. The results revealed that the increase in radiation dose resulted in removal of aflatoxin generator fungi, and there was no possibility for their growth during the 9-month storage period, thus the aflatoxin production was reported to be zero. In the control sample, however, the fungal spore increased, and the aflatoxin production was reported to be higher than the standard. Sensory evaluation revealed that there was no marked change in the pistachios’ taste up to the 5-kilogray dose, and there was no significant difference between the control sample and up to the 5-kilogray irradiated treatments (p