Test method for vitamin B12 in milk and milk powder

Abstract

A test method for vitamin B12 in milk and milk powder includes steps of a, mixing original samples of milk or milk powder quantitatively and uniformly to obtain a solvent; b, sterilizing the solvent to obtain a sterile solvent and then storing the sterilized solvent; c, preparing a culture base solution of vitamin B12, sterilizing the culture base solution to obtain a sterile base solution and then storing the sterile base solution; d, preparing standard substance solutions with different vitamin B12 concentrations; e, adding the sterile base solution, the solvent and the standard substance solutions into corresponding micropores of a microporous plate to obtain test fluids by means of incubating; f, enabling microorganisms to suspend in the test fluids and then reading the turbidities of the microorganisms by an ELISA reader; g, drawing standard curves of concentrations of vitamin B12 in the test fluids and the turbidities of the test fluids; and h, substituting the turbidity of the test fluid corresponding to the solvent into the standard curve to calculate and obtain the concentration of vitamin B12 in milk or milk powder. The test method is simple in operation, the microporous plate is disposable so that cross infection in test is avoided, and reproducibility of results is good.

Description

technical field [0001] The invention relates to a method for detecting vitamin B12, in particular to a method for detecting vitamin B12 in milk and milk powder products. Background technique [0003] At present, the detection methods for vitamin B12 at home and abroad are relatively complicated, generally including microbial methods, high performance liquid chromatography and enzyme-linked immunosorbent assays. The detection results of enzyme-linked immunosorbent assay are quite different from the actual value, and the lower limit of detection by high performance liquid phase method is much higher than that of microbial method. The microbiological method for the detection of vitamin B12 in dairy products uses Lactobacillus delbrueckii, the specificity of ATCC 7830 for vitamin B12, the acidity produced by growth in samples containing vitamin B12 and the optical density formed to determine the content of vitamin B12. Existing microbiological methods for vitamin B12 detectio...

AI Technical Summary

Problems solved by technology

However, the detection process is complicated. When using a spectrometer, each sample needs to be placed in a cuvette, which is cumbersome to operate; it is easy to cause cross-contamination, and the reproducibility of the results is not good.