Identification of Toxigenic Aspergillus Species in Rice Produced in Khuzestan and Mycotoxins in Iimported Cereals

Abstract

Background: Due to their high amount of carbohydrate and enough moisture, cereals are a good environment for the growth of toxigenic fungi. Because of the carcinogenicity and mutagenicity of mycotoxins, preventing them from entering the food chain is essential. Therefore, the present study was conducted to determine the amount and type of contaminated imported cereals and rice produced in Khuzestan province. Materials & Methods: In October and November 2015, a total of 50 random samples of rice was collected from paddy fields. Aspergillus were identified based on available diagnostic criteria and PCR. The amount and type of aflatoxin in rice samples and mycotoxins in imported cereals (winter 2015 to autumn 2016) were evaluated by HPLC. Results: Based on one sample t-test and comparing the mean of mycotoxins contaminating cereals in different seasons with national maximum standard, the amount of mycotoxins in barley and wheat were within the standard range but %8.4 of corn was higher than the permitted level (ppb5). Analysis of aflatoxins in rice also showed that 16 samples were contaminated with aflatoxin B1. Aspergillus flavus was the major pollutant (%42.1) isolated from rice. Conclusion: Aspergillus flavus is the major producer of aflatoxin B1 in domestic rice. Examination of imported cereals also showed high rates of fungal growth and production of secondary metabolites, possibly due to inadequate storage conditions, high temperature and humidity. Therefore, it is recommended to strengthen the monitoring tools in the processing and storage of rice and cereals.