Binding of aflatoxin M1 to different protein fractions in ovine and caprine milk

The affinity of aflatoxin M-1 toward the main milk protein fractions in ewe and goat milk was investigated by using an ELISA. This study took into account the possible effects of common dairy processes such as ultrafiltration, acidic or rennet curding, and production of ricotta from acidic or rennet whey. Treatments that allowed the separation of casein from whey proteins under conditions that do not alter the physical or chemical status of the proteins (such as ultracentrifugation) were used as a reference. None of the treatments used in typical dairy processes caused significant release of the toxin, in spite of the relevant changes they induced in the interactions among proteins. Only the combined heat and acidic treatment used for production of ricotta cheese altered the structure of whey proteins to the point where they lost their ability to bind the toxin. This study also showed that, regardless of the physical state of the sample, a commercial electronic nose device, in combination with appropriate statistical tools, was able to discriminate among different levels of sample contamination.