Mich. Comp. Laws § 119.56

Sec. 6. The commissioners shall cause to be kept a written or printed record of every session of the board, which record shall be public. They shall also provide for a system of accounts to conform to any uniform system required by law, and for the auditing at least once yearly of the accounts of the treasurer by a competent certified public accountant or by the auditor general of the state. The board shall require of the treasurer a suitable bond by a responsible bonding company, such bond to be paid for by the board.