Also called β-D- galactose lactase. It is mainly used in the dairy industry which serves to turn low-sweetness and low-solubility lactose into monosaccharide (Glucose and Galactose) that is sweeter and more soluble; reduce the possibility of the separation of the lactose crystal from ice cream, concentrate milk and filled milk and increase their sweetness. In ferment and baking industries, it is also used to help lactose that is not usable for ordinary yeasts to be used as it is hydrolyzed into Glucose. As a number of infants may suffer from diarrhea after they are fed milk for absence of normal lactase in their intestines, lactase and lysozyme are often added to milk for infants in many European countries.