DETECTION AND ESTIMATION OF AFLATOXIN B1 IN FEEDS AND ITS BIODEGRADATION BY BACTERIA AND FUNGI

ycological examination of 500 samples of animal feeds and feed ingredients for Aspergillus flavus and Aspergillus parasiticus revealed that 180 (36%) samples yielded isolates of Aspergillus flavus and 65 (13%) samples gave isolates of Aspergillus parasiticus. Testing of the same samples for AFB1 contamination showed that 99 samples (19.8%) contained AFB1 at a rate of 125 ppb, 45 samples (9%) at a rate of 25-50 ppb, 32 samples (6.4%) at a rate of 101-200 ppb and 19 samples (3.8%) contained aflatoxin B1 at a rate of 201-2000 ppb. Screening of isolated strains of Aspergillus flavus and Aspergillus parasiticus for aflatoxin B1 production by culturing on YES medium supplemented with 0.019% P-cresol revealed that 81 (45%) out of 180 isolates of Aspergillus flavus and 16 (24.62%) out of 65 isolates of Aspergillus parasiticus produced aflatoxin B1. Testing the ability of 4 Lactobacillus strains for removal of aflatoxin B1 from liquid media after physical and chemical treatments revealed that the acidic and heat treatments of bacterial pellets significantly enhanced their ability to bind aflatoxin B1 but heat treatment was not as effective as acidic treatment. Screening the ability of either intact mycelium or fragmented mycelium or culture cell - free system of non - aflatoxin B1 producing Aspergillus flavus and Aspergillus parasiticus indicated that fragmentation increased the ability of tested strain to degrade aflatoxin B1. Culture cell free system showed the highest percent of aflatoxin B1 degradation. Aspergillus flavus showed higher percent of degradation than Aspergillus parasiticus.