Interactive effects of duration of storage and addition of formaldehyde on levels of aflatoxin M1 in milk.

Spray-dried skim milk, naturally contaminated with aflatoxin M1, was added to either raw or pasteurized whole milk to a final concentration of 1.1 microgram aflatoxin M1/L milk. Formalin (37% w/w) was added to the milk solutions to final concentrations of 0, 0.025, 0.05, and 0.1% formaldehyde. Samples were stored in the dark at 21 degrees C in plastic and glass containers and were analyzed for aflatoxin M1 at 0, 1, 2, 3, and 4 weeks. This experiment was repeated using only raw milk and glass containers. Aflatoxin M1 analyses were done at 0, 1, and 2 weeks. Aflatoxin M1 losses increased over time and with increased formaldehyde concentration. With both experiments, aflatoxin M1, levels after 2 weeks were less than 0.05 micrograms/L in samples containing 0.1% formaldehyde.