The county auditor, or in counties that have the office of controller, the auditor-controller shall be the chief accounting officer of the county. Upon order of the board of supervisors, the auditor or auditor-controller shall prescribe, and shall exercise a general supervision, including the ability to review departmental and countywide internal controls, over the accounting forms and the method of keeping the accounts of all offices, departments and institutions under the control of the board of supervisors and of all districts whose funds are kept in the county treasury.