isolation of aspergillus flavus from feeds and determination of aflatoxin m1 in milk from some dairy farms of tehran by hplc‎‏ ‏

isolates of a. flavus obtained from different feeds such as corn, barley, wheat, cotton ‎seed, bread waste, soybean, alfalfa, wheat bran, barley meal, canola meal, corn silage and beet ‎pulp from nine dairy farms in tehran province during 2004. ability of sclerotiom production by ‎isolates was tested. results showed 62.9 percent of isolates produced sclerotiom on cza medium ‎and 68.5 percent of these isolated were aflatoxigenic. from pollution of feed by a. flavus point of ‎view in dairy farms were between 20.37 - 3.7 percent. 16.67 percent of isolates obtained from ‎beet pulp as the most contaminated feed. alfalfa, canola meal and corn meal with‏ ‏medium 1.8 ‎percent were of the least in every contaminated feeds. analysis of milk samples by hplc ‎showed that the rate of afm1 in samples varied and ranged from 0.0009 to 0.5269 ppb. ‎calibration regression coefficients determined 0.99 to 0.997 for these experiments and ‎determined recovery was between 70.31 to 1.4.93 percent in these experiments. ‎