Molecular identification of aflatoxigenic Aspergillus species in dried nuts and grains collected from Tehran, Iran

Introduction Agricultural commodities contaminated by molds and mycotoxins can be considered as public health problems in less developed countries, particularly in Iran. Hence the main purpose of this study was to identify mold fungi and molecular analysis of the most important species of aflatoxin-B1-producing Aspergillus species in some dried nuts and grains in local markets in Tehran. Materials and methods Two hundred fifty samples of wheat, rice, corn, pistachios, and peanuts were collected from the five different locations of Tehran between January 2018 and January 2019. The samples were analyzed by using direct seed inoculation method and grain crushing method. Fungal strains were identified as Aspergillus spp. on the basis of morphological characters and further confirmed by using of beta-tubulin gene sequencing. To differentiate between aflatoxigenic and non-aflatoxigenic Aspergillus spp., the isolates were screened for the presence of aflatoxigenic genes (nor-1, ver-1, omtA, and aflR). Results One-handed forty-eight aflatoxigenic Aspergillus isolates (144 A. flavus and 4 A. parasiticus) were identified and aflR gene was the most frequent gene in these species. Five isolates (4 A. flavus, 1 A. parasiticus) had quadruplet pattern, 64 isolates (63 A. flavus, 1 A. parasiticus) had more than 1 gene and 39 isolates (38 A. flavus,1 A. parasiticus) did not have any genes. Conclusion According to the contamination of dried nuts and grains by some aflatoxigenic fungi, an extensive surveillance is necessary to provide a wider view on these products. Moreover, effective and efficient aflatoxin control program requires identifying and managing key elements that are effective in reducing mycotoxin production at farm level or in storage conditions.

Automated summary

This study aimed to identify mold fungi in dried nuts and grains in Tehran, Iran, and analyze the most important species of aflatoxin-B1-producing Aspergillus species. The research found 48 aflatoxigenic Aspergillus isolates, with 144 identified as A. flavus and 4 as A. parasiticus, with the aflR gene being the most frequent. The study highlights the importance of extensive surveillance and effective control programs to reduce mycotoxin contamination in agricultural commodities.