Mich. Comp. Laws § 289.3129

Sec. 3129. (1) A local health department shall investigate an allegation of foodborne diseases and poisonings or suspected foodborne diseases and poisonings connected with food service establishments within its jurisdiction and delegated authority and shall promptly make a report of its findings to the department. (2) If an investigation indicates that a source of a foodborne disease or poisoning was from a food processing, food storage, or similar type of food establishment over which the department has legal jurisdiction or responsibility, the local health department shall immediately notify the director while the local health department is completing the investigation.