Molecular and chemical based characterization of aflatoxin producing aspergillus species obtained from stored grain samples

Abstract Background Aspergillus section Flavi is a group of widely distributed multicellular fungi associated with contamination of stored grain. Some species of it secretes aflatoxin contaminants which is a carcinogenic in nature. Due to this it poses a significant global challenge in the health, agriculture and food processing industries. The aim of present study is quantification by using a chemical based detector and molecular identification of aflatoxin producing fungi from stored grain samples of flood prone area of Bihar, India. The samples (n = 61) were investigated for the presence of aflatoxigenic fungi, which was further confirmed by HPLC-FLD. The aflatoxigenic isolates identified through amplification of the internal transcribed spacer (ITS) region. Findings A total of n = 119 fungal isolates from 5 distinct genera were isolated in PDA and CYA. The Aspergillus species were the dominant with occurrence of Aspergillus section Flavi (58.95%), Aspergillus section Nigri (35.79%), Aspergillus section Fumigati (3.16%), Aspergillus section Terrei (1.05%) and Aspergillus section Circumdati (1.05%). The positive isolates were quantified by HPLC-FLD and highest amount of aflatoxin was determined in W7 isolate of wheat as 6907.47 µg/kg of AFB1 and 68.88 µg/kg of AFB2. Further, ITS sequencing of five positive isolates for aflatoxin showed that a significant alignment of 99–100% with the previously isolated fungi A. aflatoxiformans DTO 228-G2 and A. austwickii DTO 228-F7 which was confirmed by the BLAST and all the sequences were deposited in the NCBI database. Conclusions To our knowledge, this is the initial report concerning the presence of aflatoxigenic species of A. section Flavi. Hence, to conclude contamination of food grain samples with aflatoxin producing fungi is alarming in these flood prone areas.