>Nonfat dry milk and skimmed milk powder are very similar. Both are obtained by removing water from pasteurized skim milk. Both contain 5% or less moisture (by weight) and 1.5% or less milkfat (by weight). The difference is that skimmed milk powder has a minimum milk protein content of 34%, whereas nonfat dry milk has no standardized protein level.
Nonfat dry milk and skimmed milk powder are classified for use as ingredients according to the heat treatment used in their manufacture. There are three main classifications: high-heat (least soluble), medium-heat, and low-heat (most soluble).
Nonfat dry milk and skimmed milk powders are available in roller-dried and spray-dried form, the latter being the most common. Spray-dried nonfat dry milk and skimmed milk powders are available in two forms: ordinary or non-agglomerated (non-instant) and agglomerated (instant).
Ship and store in a cool, dry environment at temperatures less than 27°C and relative humidity less than 65%. The shelf life of non-instant nonfat dry milk powder is 12-18 months; instant is 6-12 months. Note that storage life is very dependent on storage conditions, and that this figure is only a guide. Under ideal conditions, non-instant nonfat dry milk powder can retain its physical and functional properties for at least two years; however, quality will be impaired if temperatures and humidity are too high and storage is extended.