Vitamin B12 is the active corrinoid produced in cultivated white button mushrooms (Agaricus bisporus)

Analysis of vitamin B12 in freshly harvested white button mushrooms (Agaricus bisporus) from five farms was performed by affinity chromatography and HPLC-ESI-MS techniques. The vitamin B12 concentrations obtained varied from farm to farm, with higher concentrations of vitamin B12 detected in outer peel than in cap, stalk, or flesh, suggesting that the vitamin B12 is probably bacteria-derived. High concentrations of vitamin B12 were also detected in the flush mushrooms including cups and flats. HPLC and mass spectrometry showed vitamin B12 retention time and mass spectra identical to those of the standard vitamin B12 and those of food products including beef, beef liver, salmon, egg, and milk but not of the pseudovitamin B12, an inactive corrinoid in humans. The results suggest that the consumer may benefit from the consumption of mushroom to increase intake of this vitamin in the diet.