THE BACTERIOLOGY OF DRY MILK

Abstract

A significant factor in extending the practical utility of dry milk for infant feeding is its high degree of bacterial purity and freedom from infectious organisms. Before reviewing the research which has established the fact that although properly prepared dry milk is not sterile in the strict bacteriologic sense, it contains relatively few harmless saprophytic species, it seems desirable to indicate briefly the factors contributing to the bacterial flora usually found in dry milk prepared by the two common processes. Since the application of heat by either method does not sterilize the milk completely, certain species which are present normally in the original fluid milk are found in the final product. In addition to these residual species, milk powder, as it is found on the market, may contain additional numbers and varieties of bacteria introduced by recontamination between the actual drying operation and the final packing. Even though these general