159.48 Levy of ad valorem taxes by board of county commissioners.—The exercise of the powers granted industrial development authorities is declared to be a public and county purpose. The board of county commissioners is authorized to, and may, levy ad valorem taxes in an amount not to exceed 1 mill annually for the purposes of ss. 159.44-159.53. The proceeds of such ad valorem tax shall be used to aid each industrial development authority in fostering, developing, and locating industry in the county and to pay the reasonable operating expenses of the authority to the extent that the board of county commissioners finds necessary. No ad valorem taxes shall ever be used for the purpose of paying the interest or principal on any bonds issued to finance or refinance an industrial or manufacturing project as prohibited by the State Constitution.