USING direct-plating technique, thirty-nine species belonging to
16 fungal genera were isolated from maize and sorghum grain
samples (20 samples each) on Czap ek's agar (Cz) and Czap ek's
supplemented with 40% sucrose agar (Cz40S) media at 28ºC. Widest
spectrum of genera and species were recorded on sorghum (16 genera
and 35 species) compared with maize grains (8 and 19). The highest
total counts (139 CFUs/ 100 grains) and the number of genera (14)
and species (27) were identified from sorghum grains on Cz medium.
The most common fungi on the grains tested were Aspergillus flavus,
A. niger, Eurotium amstelodami, E. rubrum, E. repens, Fusarium
verticillioides and Rhizopus stolonifer. Among 129 isolates screened
for their abilities to produce amylase enzyme, 102 isolates could
produce this enzyme, of which A. terreus exhibited the highest
production (EI=1.73). HPLC analysis revealed that out of 6 strains of
A. flavus tested, strain No. AUMC 11311 showed the highest
production of aflatoxin B1 and B2, while the highest value of aflatoxin
G2 was produced by strain No. AUMC 11317. It could be concluded
that fungi growing on grains and their abilities for producing enzymes
and aflatoxins might cause deterioration and spoilage of these grains.