Abstract: Objective: To present a microbiological method for the detection of biotin, folic acid and vitamin B12 in infant formula powder. Methods: For quantification of these vitamins, the growth of the lactic acid bacteria with specific sensitivity to them was measured after incubation in their presence. Thirteen samples of commercial infant formula powder were detected by the proposed method. Results: More stable and repeatable data were obtained from the determination of biotin and vitamin B12 by the microbiological method with a relative standard deviation (RSD) of 0.056%～4.158% and 0.112%～3.848%, respectively, while the results obtained for folic acid varied in a wide range with a RSD of 1.236%～8.332%. Conclusion: This method is suitable for the quantitative analysis of the vitamins biotin, folic acid and vitamin B12 in infant formula powder.

Key words: microbiological method; infant formula powder; vitamin

摘要： 目的:采用微生物法测定婴幼儿配方乳粉中生物素、叶酸和VB12.方法:利用不同乳酸菌对特定维生素具有敏感性的特点,通过测定菌株的生长变化来反映样品中相应微生物的维生素含量,对市售的13种婴幼儿配方乳粉维生素进行测定.结果:微生物法对于生物素和VB12测定数据更稳定,重复性好,生物素相对标准偏差为0.056％～4.158％,VB12的相对标准偏差范围为0.112％～3.848％,而叶酸的检测数据之间波动稍大,相对标准偏差为1.236％～8.332％.结论:本法适合婴幼儿配方乳粉中生物素、叶酸和VB12这3种维生素的分析定量研究.

关键词: 微生物法；婴幼儿配方乳粉；维生素