Dry Milk Storage Tips

Nonfat dry milk, included in most home-storage programs, provides a well-balanced protein. It contains all of the essential amino acids (proteins) needed in the diet.

If nonfat dry milk is not stored properly, however—exposed to excessive temperature and humidity for long periods of time—it will darken in color. This indicates a chemical reaction involving milk sugar (lactose) and certain amino acids—among them lysine. When lysine reacts with lactose in nonfat dry milk, the lysine, an essential amino acid, becomes nutritionally unavailable.

Nonfat dry milk is a good storage food because of its low moisture and fat content. Recently scientists analyzed a nonfat dry milk sample which had been stored for twenty years; 70 percent of the lysine was still available. Subsequent feeding studies demonstrated that this old nonfat dry milk still promoted good growth in experimental animals.

In another study, an analysis of low moisture (2.8 percent) samples of nonfat dry milk showed no change in value after a two-year storage period, regardless of temperature. But milk powder with 5 to 7 percent moisture deteriorated within a matter of weeks. Hence, a low-moisture nonfat dry milk should be selected for long-term storage, and the product should preferably be stored under cool, dry conditions. Clayton S. Huber, Department of Food Science and Nutrition, Brigham Young University, Provo, Utah