Stability of aflatoxin M1 during manufacture and storage of yoghurt, yoghurt-cheese and acidified milk
1994
Hassanin, N.I.
Yoghurt, yoghurt-cheese and acidified milk were prepared from pasteurised half-cream milk, naturally contaminated with aflatoxin M1 (AFM1) and then were stored at 4 degrees C for 2 weeks. Levels of AFM1 in these dairy products were high, and then began to decrease during storage period at 4 degrees C. Most of the AFM1 (recoveries of 71%) appeared in yoghurt-cheese after 14 days, this is due to AFM1 being associated with casein fraction. Whereas pH values of yoghurt-cheese during refrigerator storage ranged from 5.15 to 4.65 and titratable acidity ranged from 3.9 to 3.5 g lactic acid litre(-1), whilst AFM1 (recoveries of 41%) from yoghurt after manufacture and storage was much more susceptible to reduction by storage this is due to the higher acidity (range 2.3-3.1 g litre(-1)) of yoghurt by the action of microorganisms, besides the changes in pH values (5.10-4.70). When acidified milk was used the recoveries of toxin were 34.2% after 2 weeks; pH values ranged from 2.95 to 2.85 and titratable acidity ranged from 2.3 to 2.2 g litre(-1) during storage.
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