不同品牌乳酸菌国标检验MRS琼脂培养基质量比对研究

Comparative study on the quality of MRS AGAR medium tested by different brands of lactic acid bacteria

目的考察市售5个国产品牌和2个进口品牌的MRS琼脂培养基对乳酸菌的培养效果,比较国内外不同品牌培养基的产品质量。方法采用螺旋涂布计数的方法,对3株GB 4789.28—2013中规定的乳酸菌和9株非国标规定乳酸菌(包括标准菌株和实验室分离菌株)在5个国产品牌和2个进口品牌的MRS琼脂培养基上的生长情况进行定量测定。通过比较不同品牌培养基对不同菌株的生长率,对各品牌培养基质量进行评价。结果 GB 4789.28标准菌株在不同品牌MRS琼脂培养基上的生长率存在明显差异,部分培养基存在质量问题。从益生菌粉中分离的嗜热链球菌ST-21在参比培养基生长能力良好,且不同品牌MRS琼脂培养基上的生长率存在显著差异。结论本研究结果表明目前市售的国内外不同品牌MRS琼脂培养基质量存在较大差异;嗜热链球菌ST-21可有效评价不同品牌培养基质量差异,适宜用于MRS琼脂培养基的质量控制。

Objective To investigate the culture effect of MRS AGAR medium of 5 domestic brands and 2 imported brands on lactic acid bacteria, and to compare the product quality. Methods Using spiral coating counting method, the growth of 3 strains of lactobacillus specified in GB 4789.28—2013 and 9 strains of non-national standard Lactobacillus(including standard strains and laboratory isolated strains) on the different MRS AGAR medium were quantitatively determined. By comparing the growth rate of different brands of medium to different strains, the quality of each brand of medium was evaluated. Results There were significant differences in the growth rate of GB 4789.28 standard strain on different brands of MRS AGAR media, and some of the medium had quality problems. Streptococcus thermophilus ST-21 isolated from probiotics powder had good growth ability in reference medium, and there were significant differences in growth rate among different brands of MRS AGAR medium. Conclusion The result of this study indicated that there are great differences in the quality of MRS AGAR media of different brands at home and abroad;Streptococcus thermophilus S-T21 can effectively evaluate the quality difference of different brands of media, and is suitable for the quality control of MRS AGAR media.