MYCOFLORA AND AFLATOXIN-PRODUCING STRAINS IN ANIMAL MIXED FEEDS

The mycoflora of 69 samples of animal mixed feeds were studied. Fungal counts ranged from 10(2) to 10(8) CFU/g, the lowest counts corresponding to the samples of rabbit feeds. Seventy-one fungal species belonging to 26 genera were identified. The predominant species were Aspergillus flavus, Fusarium moniliforme, and Penicillium chrysogenum. Thirty-six strains of A. flavus and one strain of A. parasiticus were screened for aflatoxin production in yeast extract-sucrose medium. The final pH, weight of mycelium, and production of aflatoxins were determined after 14 days of incubation. Five strains (13.5%) were aflatoxigenic. No statistical differences were observed in mycelial dry weights and final pH between aflatoxin-producing strains and nonaflatoxigenic strains.