Ill. Admin. Code tit. 77, § 785.563 – Operations and Operating Procedures – Pasteurization

a) All milk, buttermilk and whey used in the manufacture of dry dairy products shall be pasteurized at the plant where dried, except that condensed whey and acidified buttermilk containing 40 percent or more solids may be transported to another plant for drying without repasteurization. Milk or skim milk to be used in the manufacture of nonfat dry milk shall be heated prior to condensing to at least the minimum pasteurization temperature of 161º F. for at least 15 seconds or its equivalent in bacterial destruction. Condensed skim made from pasteurized skim milk may be transported to a drying plant, provided that it shall be repasteurized at the drying plant, prior to drying, at not less than 175º F. for 25 seconds or its equivalent in bacterial destruction.
b) All buttermilk or cream from which it is derived shall be pasteurized prior to condensing at a temperature of 185º F. for 15 seconds or its equivalent in bacterial destruction.
c) All cheese whey or milk from which it is derived shall be pasteurized prior to condensing at a temperature of 161º F. for 15 seconds or its equivalent in bacterial destruction.