Whole milk powder contains either 26% or 28.5% milkfat. Dry whole milk is available in either spray-dried or roller-dried forms. Roller-dried whole milk powder is often used in chocolate production because more free fat is available. Whole milk powder has a shorter shelf life than nonfat dry milk. For maximum stability, store whole milk powder in a cool, dry place. Milkfat is susceptible to oxidative reactions that are accelerated by increased temperature. Whole milk powder is sometimes packaged with a nitrogen flush to extend its shelf life.