Municipalities within the State of Mississippi are hereby authorized to contribute funds to the support of the federal food stamp program, operated under the direction of the United States Department of Agriculture, and administered in the State of Mississippi by the state department of public welfare. Contributions to the support of the federal food stamp program may be made by municipalities from general funds or from the proceeds of municipal sales taxes. However, no municipality shall establish a federal food stamp program where the county in which said municipality is situated has such a program in operation.