ABSTRACT
All the B-group vitamins can be assayed microbiologically. The assay organisms are particular strains obtained from various culture collections such as the American Type Culture Collection (ATCC). The current and previous names of the microorganisms used in this chapter are listed in Table 18.1. With the exception of vitamin B6, official (AOAC) microbiological methods for determining B-vitamins in foods (Table 18.2) employ lactic acid bacteria, and measure either the lactic acid produced after a 72-h incubation period (titrimetric method) or the growth of the organism (turbidimetric method). The latter is nowadays generally preferred, as it is simpler and requires shorter incubation times. Methods based on the measurement of metabolic carbon dioxide have also been developed.
