A biocidal additive package comprises at least one metal or metal containing compound selected from the group consisting of Cu2O, Cu(OH)2, Cu, CuO3, Cu2O3, and a combination thereof, and at least one non-copper metal or non-copper containing metal compound. Non-limiting examples of non-copper metal and non-copper containing metal compounds are Ag, Ag2O, Bi, Bi2O3, Zn, ZnO, or a combination thereof. A biocidal ceramic glaze layer and an article comprising a biocidal ceramic glaze layer are provided. Also provided is a method of affixing a biocidal ceramic glaze to a substrate.
