The present invention pertains to methods of preventing and eliminating trisulfide bonds in proteins such as antibodies. In one embodiment, trisulfide bonds in proteins are converted to disulfide bonds as part of chromatographic purification procedures. In another embodiment, the formation of trisulfide bonds in proteins is inhibited by implementation of methods described herein during the cell culture production of such proteins. In another embodiment, monoclonal antibodies are produced by the methods described herein.