Abstract
Thirty one species belonging to 17 fungal genera were found to be associated with sorghum (Sorghum bicolor) grain samples imported to the Kingdom of Saudi Arabia. An agar plate method was used to screen 24 samples collected from different markets located in Riyadh region. Statistical comparisons of fungal isolation frequencies revealed that Aspergillus niger, Penicillium funiculesum and Rhizopus stolonifer were most frequently isolated from untreated grains, while A. niger, P. funiculesum and F. semitectum, were most dominant in surface-sterilized grains. Significant correlation coefficients were observed among frequencies of some fungal species. Mycotoxin investigations using HPLC revealed that mycotoxin-producing isolates varied in the type and concentration of toxins produced. A. niger isolates were the highest producers of aflatoxins, followed by A. flavus var. columnaris and A. terreus, P. funiculosum was the highest producer of the Penicillium toxin Patulin (41 ppb), while P. oxalicum was the highest producer of citreoviridin (10 ppb). F. verticillioides was the highest producer of the Fusarium toxins fumonisin (19.1 ppb) and Zearalenone (21.4 ppb). F. nygamai was the highest producer of vomitoxin (31.3 ppb). Two of the three Alternaria isolates were altenuene producers.