Michigan Compiled Laws, Chapter 288. Dairy Industry § 288.731

Sec. 171. (1) A person that manufactures or processes cheese shall pasteurize milk to be used for making cheese or cheese culture by subjecting every particle of the milk to a minimum temperature of 161°F (72°C) for not less than 15 seconds or to other pasteurization temperature and time standards listed in section 137,  1 except as provided for in section 138.  2 A person that manufactures or processes cheese shall equip high temperature short-time pasteurization units with the proper controls and equipment to assure pasteurization. Milk held more than 2 hours between time of receipt or pasteurization and culturing shall be cooled to 45°F (7°C) or lower, until the time of culturing.

(2) A person that manufactures or processes cheese and engages in vat pasteurization shall use only equipment meeting the requirements of sanitary standards.