Pistachio is one of the valuable export products very susceptible to infection by A. flavus. The present study aimed to investigate the effect of coating fresh pistachio with hydrocolloid methylcellulose on aflatoxin amount during storage. In this study, pistachio seeds from the Abbasali cultivar were used. Methylcellulose solution with different concentrations (0.1%, 0.5%, 1%, and 2%) was prepared and a coating of this hydrochloride was created by immersing methylcellulose on pistachio samples. The coated samples and the control sample (uncoated) were kept in an incubator at a temperature of 25°C for 3 months. In the investigation of the impact of various methylcellulose concentrations in the composition of the pistachio kernel coating, on the inhibition rate of this micro colloid on the production of total aflatoxin and B1, B2, G1, and G2 aflatoxin which was measured by HPLC, showed that concentrations of 0.1% and 0.5% reduced total aflatoxin production significantly, it increased about 3.5 times after three months of storage. Also after 3 months of storage, aflatoxin B1, B2, G1, G2 in the samples coated by 0.5% and 0.1% methylcellulose was decreased to undetectable toxin production. Also, evaluation of moisture content revealed that the pistachio seed coated with methylcellulose had the highest moisture content at 2% and the lowest at 0.1% and 0.5% of the control samples. پرونده مقاله