Radiometric-Microbiologic Assay of Niacin Using Kloeckera brevis: Analysis of Human Blood and Food

Abstract
Kloeckera brevis, a yeast, was used as the test organism for the development of a radiometric-microbiologic (RMA) assay for niacin. The assay was determined to be sensitive to the 2 ng niacin per vial level and specific for the biologically active forms of this vitamin. The method was shown to be simple, accurate, and precise in the analysis of niacin in human blood and food. The application of the radiometric technique eliminates some of the problems encountered with conventional turbidimetric-microbiologic assay.