Natural (Unhydrolyzed) Milk Versus Lactose-Hydrolyzed Milk for Cultured Dairy Products: Physiological and Practical Implications for the Starter Industry.

As a microbiological medium, lactose-hydrolyzed milk is quite different from natural milk in that the restrictive role of milk lactose (the major energy source for microorganisms) is eliminated. To emphasize the restrictive role of lactose, the enzymatic and genetic mechanisms involved in the utilization of this beta-galactoside are discussed. Elimination of this selectivity leads to certain manufacturing and storage difficulties with cultured dairy products. This important change in the raw material (milk) should be recognized in selection of starter strains for use in conversion of lactose-hydrolyzed milk to cultured dairy products.