Milk solids not fat shall mean and include skim milk, concentrated (evaporated or condensed) skim milk, superheated condensed skim milk, sweetened condensed skim milk, nonfat dry milk solids, edible dry whey, cheese whey, sweet cream buttermilk (whether fluid, condensed or dried), and any of the foregoing products from which all or a portion of the lactose has been removed after crystallization, or the lactose has been converted to simple sugars by hydrolysis.
Cal. Code Regs. Tit. 3, § 457