Nonfat dry milk is made of fresh
whole milk from which both water and fat have been removed.
After the fat has been removed, the skim milk is pasteurized
and about two-thirds of the water removed under vacuum.
This concentrated skim milk is dried by spraying it into a
chamber of hot, filtered air .The resulting product is a fine-textured powder of very low moisture content.
A further step, the instantizing process, produces a dry
milk that dissolves in water instantly. By one method, the dry
milk is moistened with steam, then redried. Except for small
losses in ascorbic acid, vitamin B12, and biotin, the processing
has no appreciable effect on the nutritive value. The presence
of the milk fat does require special packaging to prevent oxidation during storage.