Systems and methods for printing and verifying product codes using ultraviolet (UV) fluorescing ink include, in at least one aspect, a system including: a UV light source configured and arranged to illuminate, with UV light, product codes printed on products; a camera configured and arranged to capture visible light emitted by a single ink of the product codes responsive to the illumination with the UV light, where the single ink includes a combination of a non-fluorescing substance and a UV fluorescing substance; and a controller coupled with the camera and configured to perform machine vision processing on the captured visible light to identify and confirm the product codes printed on the products.