This European Prestandard specifies a method for the determination of total vitamin B6 in foodstuffs by microbiological assay (MBA). Vitamin B6 is determined as the mass fraction of pyridoxine, pyridoxal and pyridoxamine, including their phosphorylated or glycosylated derivatives. It is usually expressed as milligram vitamin B6 per 100 g of foodstuff. The method is applicable to samples that can be rendered homogeneous and do not contain high concentrations of antibiotics or other interfering substances.