The Vitamin B12 Content of Certain Fishery Materials

Abstract

Irregularities occurring in the microbiological assay of herring (Clupea pallasi) materials for vitamin B12 (cobalamin) are described and the probable reasons for the differences discussed. With the employment of a Lactobacillus leichmannii assay procedure and conditions under which vitamin B12 (cyano-cobalamin) and vitamin B13a (hydroxo-cobalamin) caused identical growth response, it was found that normal commercial flame-dried herring meals had about the same total cobalamin content as specially prepared meals dried at 38° to 43.5 °C. Chromatographic separation, elution and assay of the cobalamins in herring-meal samples indicated that substantially all of the activity found by direct assays of the meals was due to the vitamin itself. Hexane extraction had little effect on the cobalamin content, but heating the meals reduced it.