Determining the kinetic behaviour for the secretion of milk toxin as related to dosage level of aflatoxin B1.

39 species which belong to 14 genera were isolated from 110 milk samples collected from different dairy sources at Assiut City. The most frequent fungi were A. niger, A flavus and Clasdosporium cladosporioides, followed by Curvularia spicifera and Penicillium corylophilum. The remaining species were of rare occurrence. The fluorescence-method for detecting aflatoxin-producing strains demonstrated the presence of two isolates namely A. flavus possesses this property. One of these toxic isolates was proved to produce high level of aflatoxin B1. It was used as a tool for determining the kinetic behaviour for the secretion of M1 toxin in milk of lactating animals which had received a toxic diet. The results revealed the following: 1. The milk toxin was detected in the milk of lactating animals next day after the toxin-containing ration was fed. 2. The level of milk toxin is gradually decreased when the feeding programme was interrupted. 3. When the animals supplied a ration containing the same concentration of aflatoxin for successive days, the milk toxin concentration was maintained at the same level. 4. The total amount of milk toxin secreted was less than one per cent of the amount of aflatoxin B1 received. 5. The concentration of milk toxin secreted by goats was higher than that of dairy cows. 6. Milk toxin failed to be detected five days after the feeding programme was discontinued.