Tenn. Code Ann. § 5-8-203

When the contract has been signed on the part of the county, and also signed by the proper officers, on the part of the bank or banks under the seal thereof, and a good and sufficient bond has been executed by the bank or banks, for the faithful performance of the contract and to save the county harmless, the finance committee shall so notify the county trustee, in writing, and order the county trustee to place all funds already in the county trustee's hands or that may thereafter be collected by the county trustee on deposit in the bank or banks, noting the funds that shall draw interest and the amount thereof.