Population Density of Aspergillus Species Belong to Section Flavi and Nigri on Pistachio Nut in Kerman Province

Iran is one of the biggest producer and exporter of pistachio nut around the world as well as the area under cultivation. Aflatoxin contamination is a major issue in food safety affecting the whole chain pistachio production. As pistachio nut infection occurs during the maturation period before harvest, the population density of Aspergillus sections Flavi (aflatoxin producers) and Aspergillus section Nigri (dominant saprophytic) were determined in cracked, fall to the ground, in contact with the ground, located at a height of more than one meter and four cardinal directions pistachios, during the second half of June to early September 2011-2012. To determine the density of fungal species, Blotter test and serial dilution method by AFPA and CZ media were used. Overall, the density of the fungal species in different assessed pistachios decreased in the order of cracked, fall to the ground, in contact with the ground, the four cardinal directions, and more than one meter in height, respectively. The frequency of Nigri section significantly was higher than Flavi ones. There were also significant differences between sampling times, and density of fungal species was at the highest level closer to harvest time. The results could show the critical points to manage aflatoxin contamination in pistachio nuts using different approaches.