Rapid method for analysis of aflatoxin M1 in dairy products

Four methods for determining aflatoxin M1 levels in fluid milk were compared in a search for a simple, routine analytical procedure.. Each method was tested with samples spiked at levels of 0, 0.1, 0.5, and 1.0 ppb. The 3 quantitative methods were comparable in sensitivity (0.1 ng/mL) and recoveries (80-90%). A new method, using a commercially available extraction column that contains an inert hydrophilic matrix to permit extraction of dairy products, is described. The milk is adsorbed on the column and aflatoxin M1 is eluted with chloroform-acetone (9 + 1). The extract is further purified on a small silica gel column and aflatoxin M1 is determined by TLC. This method was simpler and shorter, and was equally sensitive and reproducible in determining aflatoxin M1 in spiked and naturally contaminated fluid milk samples and in spiked nonfat powdered, condensed, and evaporated milk.