The administrator in charge of a particular institution, with the consent and approval of the director of human services, shall determine the number of subordinate officers and employees for the institution. Subject to this chapter, the officers and employees shall be appointed and discharged by the superintendent or business manager pursuant to chapter 8A, subchapter IV. The superintendent shall keep, in the record of each subordinate officer and employee, the date of employment, the compensation, and the date of each discharge, and the reasons for discharge.