The invention relates to a zinc-enriched biomass comprising living or subsequently killed micro-organisms, selected from the group consisting of Streptococcus thermophilus and Bifidobacterium animalis subsp. lactis and combinations thereof, a method for the manufacture of said zinc-enriched biomass, as well as food preparations, nutraceutic products, functional foods, cosmetic and cosmeceutic products, and food supplements, comprising the said biomass. Furthermore, new micro-organism strains are described which are able to concentrate zinc within the cell in very high amounts and therefore are particularly suitable for use in the method of the invention.