A method of treating leather or hide is provided whereby a biocide and one or more detectable tags are applied to a piece of leather or hide. The detectable tag(s) can be detected to indicate one or more pieces of information, such as that the biocide has been applied to the piece of leather or hide and/or other information. Information about the biocide and the tannery that applied the biocide or other information can be discerned from detecting the detectable tag or from one or more of the detectable tags if used. A system for tagging leather or hide and applying a biocide are also provided as are methods and systems for detecting the tags.
