(1) It is expressly provided that the salaries fixed in Sections 25-3-31 through 25-3-35 shall be the full and complete compensation for all public duties rendered by all public officers and public employees designated therein whatever the source of funds, whether appropriated from the State General Fund or allotted from federal funds received by the respective state agencies where such officers and employees are employed. All laws, parts of laws, regulations, or other authority which may have heretofore provided supplemental compensation or expenses of which no itemization therefor was made to the State Auditor of Public Accounts are hereby invalidated and held for naught.
(2) In the event the Commissioner of Public Safety and the highway patrol chief are entitled to longevity pay as provided by law, this section shall not be construed to prohibit the payment thereof.
(3) This section shall not be construed to affect employees of the Mississippi State Penitentiary, the Department of Mental Health and the Governor as pertains to housing, medical care, wholesale food purchases, and other financial benefits or emoluments as pertains to their state employment.