Objective To establish a method for the determination of trace vitamin B12 in enteral nutrition powder by microbiological method. Methods The test organism was Lactobacillus leichmamii. The medium without vitamin B12 was used as assay medium. The sample were incubated for 19~20 h at the temperature of (36±1) ℃ and measured by microbial turbidimetric method. Results Vitamin B12 had a good linear relationship in the range of 0.001~0.010 ng/mL, and the content of vitamin B12 in enteral nutrition powder was 2.9 μg/100 g. Conclusion This method is accurate and reliable, and suitable for the assay of trace vitamin B12 in enteral nutrition powder.
标题：微生物法测定肠内营养粉剂中微量维生素 B12的含量
英文标题：Determination of trace vitamin B12 in enteral nutrition powder by microbiological method
