Easy to use microbiological microtiter plate test for the quantification of total vitamin B12 (enriched and natural vitamin B12) in food, feed and pharmaceutical products.
Vitamin B12 is extracted from the sample and the extract is diluted. The diluted extract and the vitamin B12 assay-medium are pipetted into the wells of a microtiter plate which is coated with Lactobacillus delbrueckii subsp. lactis (leichmannii). The growth of Lactobacillus delbrueckii is dependent on the supply of vitamin B12. Following the addition of vitamin B12 as a standard or as a compound of the sample, the bacteria grow until the vitamin is consumed. The incubation is done in the dark at 37 °C (98.6 °F) for 44 – 48 h. The intensity of metabolism or growth in relation to the extracted vitamin B12 is measured as turbidity and compared to a standard curve. The measurement is done using an microtiter plate spectrophotometer at 610 – 630 nm (alternatively at 540 – 550 nm).
|Test format||Microtiter plate with 96 wells (12 strips with 8 removable wells each)|
|Incubation time||44 - 48 h in the dark at 37 °C (98.6 °F)|