Abstract
The turbidimetric methods in routine use at two laboratories for the microbiological assay of vitamin B12 have been compared. Attempts were made to standardize some major parts of the method, i.e., assay design, test strain (Lactobacillus leichmannii), test medium, and reference standard. The laboratories used different approaches to achieve efficient assay procedures. During a 6-year period four comparative experiments were carried out. In these experiments the vitamin B12 content of five different products was determined in a series of independent assays at each laboratory. A satisfactory degree of agreement (difference less than 5%) was found for four of these products.
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Selected References
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- HOFFMANN C. E., STOKSTAD E. L. R. The microbiological assay of vitamin B12 with Lactobacillus leichmannii. J Biol Chem. 1949 Dec;181(2):635–644. [PubMed] [Google Scholar]
- Koch A. L. Turbidity measurements of bacterial cultures in some available commercial instruments. Anal Biochem. 1970 Nov;38(1):252–259. doi: 10.1016/0003-2697(70)90174-0. [DOI] [PubMed] [Google Scholar]
- SKEGGS H. R., NEPPLE H. M., VALENTIK K. A., HUFF J. W., WRIGHT L. D. Observations on the use of Lactobacillus leichmannii 4797 in the microbiological assay of vitamin B12. J Biol Chem. 1950 May;184(1):211–221. [PubMed] [Google Scholar]
- SOKOLSKI W. T., STAPERT E. M., FERRER E. B. LIQUID NITROGEN FREEZING IN MICROBIOLOGICAL ASSAY SYSTEMS. I. PRESERVATION OF LACTOBACILLUS LEICHMANNII FOR DIRECT USE IN THE VITAMIN B12 ASSAY. Appl Microbiol. 1964 Jul;12:327–329. doi: 10.1128/am.12.4.327-329.1964. [DOI] [PMC free article] [PubMed] [Google Scholar]