Stability of aflatoxin M in milk.
This three-part study was designed to determine aflatoxin M recovery from pasteurized and/or stored cow's milk. (a) Aflatoxin M was added to samples of raw Holstein milk at a concentration of 2.0 mug/liter. Half of each sample then was pasteurized at 63 C for 30 min, and both raw and pasteurized portions were stored at 4 C up to 17 days. (b) Samples of raw milk, pasteurized (77 C, 16 s) skim milk, dry cottage cheese curd, and cottage cheese whey were taken from a commercial operation in an area in which natural contamination had been encountered. (c) Milk from a cow dosed with aflatoxin B1 was stored frozen (-18 C) in bulk and in assay-size sample containers for 120 days. Aflatoxin M was recovered completely after either storage or pasteurization in (a) and (b). In (c), a recovery deficiency was detectable after 68 days of storage, which increased to 45% of the original value by 120 days. These observations differ from those of others in that loss of aflatoxin M was significant after pasteurization or storage of raw milk, totaling 87% loss after 120 days of frozen storage. Aflatoxin M partitioning between curd and whey in the preparation of cottage cheese agrees with more recent studies, but differs from previous reports. Three possible explanations for the differences are offered.
D000348:Aflatoxins / Q000032:analysis; D000818:Animals; D002417:Cattle; D002611:Cheese / Q000032:analysis; D004355:Drug Stability; D005506:Food Contamination / Q000517:prevention & control; D005519:Food Preservation; D005525:Food-Processing Industry; D005615:Freezing; D006358:Hot Temperature; D008892:Milk / Q000032:analysis; D012034:Refrigeration; D013997:Time Factors
D000348:Aflatoxins