From single-component feeds, such as cereal, bran, oil meal, animal feed, dried grass, agricultural meal cake, and corn cob meal, were obtained 56 isolates of Aspergillus, of which 32 were identified as A. flavus. Cereal, bran, and oil meal were contaminated with large numbers of fungi and yeasts. Cereal, bran, and dried grass were contaminated with relatively large numbers of bacteria. The isolated fungi were Aspergillus (64%), Penicillium (32%), Mucor (20%), Absidia (17%), Rhizopus (15%), Cladosporium (10%), Scopulariopsis (10%), Fusarium (9%), Syncephalastrum (9%), Phoma (7%), Paecilomyces, and Mortierella.