Abstract
A survey of fungi associated with corn and popcorn samples, collected from markets throughout the Riyadh region of Saudi Arabia, was investigated. Seventeen species belonging to nine genera were recovered from corn grains, while 11 species belonging to six genera were recovered from popcorn grains. Frequencies of the isolated genera were statistically compared. Aspergillus flavus, A. niger and Rhizopus stolonifer were most frequently isolated from non-sterilized grains, Aspergillus niger, Fusarium proliferatum and F. verticillioides were dominant in sterilized corn grains, while Aspergillus clavatus, A. flavus var. columnaris and Fusarium subglutinans were dominant in sterilized popcorn grains. Potential ability to produce aflatoxins (AFs) B1, B2, G1 and G2, was studied for isolated cultures by using HPLC analysis. Most A. flavus isolates (75%) and some A. niger isolates (25%) were toxin producers. About 67% of A. flavus var. columnaris isolates produced aflatoxins, mostly B2, while A. flavus produced mostly B1, G1 and G2 aflotoxins. A. niger produced the least aflatoxin levels. These findings indicate that aflatoxigenic A. flavus is predominant in imported corn which may lead to contamination of this food item with aflatoxins. Thus, more effort should be made to minimize the risk of aflatoxin accumulation in imported commodities.