Investigation of fungi isolated from stored yellow maize (Zea mays L.) in different regions of Iraq, and evaluation of aflatoxin B1 production by Aspergillus flavus isolates

Abstract

      Stored yellow maize (Zea mays L.) provides a favorable substrate for fungal colonization, particularly under warm and humid conditions, which can lead to contamination with toxigenic species and aflatoxins. This study aimed to survey the mycobiota associated with stored yellow maize grains from different regions of Iraq and to assess the aflatoxin B1(AFB1)–producing potential of Aspergillus flavus isolates. Fungi were isolated and identified based on their macroscopic and microscopic characteristics using standard taxonomic keys. The fungal community was dominated by Aspergillus spp. 31.2% , followed by  Penicillium 20.9%, Fusarium  18.7% and Alternaria 17.6% whereas Trichoderma and Rhizopus were less frequent 7.5% and 4.1% respectively. Isolates of A. flavus were subsequently screened for AFB1 production using thin-layer chromatography, and toxin levels in representative isolates were quantified by high-performance liquid chromatography. Aflatoxin B1 production was confirmed in a high proportion of the A. flavus isolates, and some strains exhibited relatively elevated AFB1 concentrations reaching 126.9 ppb and 112.6 ppb. Overall, these findings indicate a substantial prevalence of potentially toxigenic A. flavus in stored maize in Iraq and highlight the need for improved post-harvest handling, better storage conditions and regular monitoring of aflatoxin contamination to safeguard food and feed safety.