Upon the opening of the sealed proposals, the county government, after consultation with the commission, shall award said contracts, but no contract shall be awarded to any other than the lowest bidder except with the unanimous approval of the members of the county government and the recommendation of the commission, and provided the county government shall set down in its minutes the reason or reasons for granting the contract to the person other than the lowest bidder. As a condition of the letting of the contracts, the county government shall require the successful bidder to enter into a bond for the faithful performance of such contract. The county government shall have the power to reject all bids.