Mich. Comp. Laws § 288.631: Testing frequency for dairy products; testing dairy farm water supplies.

Sec. 71.

All dairy products shall be tested at a minimum frequency of 4 out of every 6 months, or as determined by the director.

Except when the water supply is required to be tested annually as provided in section 130(9)(h), well water samples for dairy farms shall be tested a minimum of once every 3 years and found to be of safe and satisfactory quality.

Water supplies for dairy plants shall be tested a minimum of once every 6 months.

Recirculated water or recirculated cooling medium shall be tested a minimum of once every 6 months.

Condensate recovery water shall be used only in applications that conform to requirements and procedures accepted by the United States food and drug administration or the director.