Mich. Comp. Laws § 286.405

Sec. 5. All orders shall be effective upon posting the same prominently in at least 5 of the most public places within the affected area. They shall be published in the administrative code, provided for in Act No. 88 of the Public Acts of 1943, as amended, being sections 24.71 to 24.82 of the Compiled Laws of 1948, but publication within the quarterly supplement to the administrative code shall not be a condition precedent to their effectiveness.