Characterization of Vitamin B-12 Compounds in Commercially Available Livestock Livers Used as Foods

Although cow livers are a good source of vitamin B-12, it is unclear whether the liver contains inactive corrinoid compounds, such as pseudovitamin B-12, most commonly found in foods. Thus, we characterized vitamin B-12 compounds in cow, pig, and chicken livers using high-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) after immunoaffinity purification. A primary peak of vitamin B-12 (approximately 90%) and several minor peaks were observed during the HPLC of the compounds purified from these livers. Furthermore, LC-MS/MS indicated that these livers contained various corrinoids (approximately 10%), such as factors III, A, S, pseudovitamin B-12, and vitamin B-12 monocarboxylic acids. This study is the first to report that commercially available livestock liver contains various corrinoid compounds that are inactive in humans.