乳酸菌菌粉定量计数方法研究

目的:以9株乳杆菌、6株双歧杆菌、3株球菌、1株凝结芽孢杆菌菌粉为研究对象,在国标GB 4789.35-2016的基础上,对稀释倍数、稀释液成分、培养基成分进行比较研究,考察对乳酸菌菌粉计数活菌数的影响。方法:采用稀释平板计数的方法,对不同的乳酸菌菌粉进行活菌计数。结果:初始乳酸菌菌粉样品稀释倍数对最终计数活菌数无明显影响,ISO稀释液对部分乳杆菌、双歧杆菌菌粉的活菌计数结果有显著提高(P<0.05);双歧杆菌菌粉采用TOS琼脂培养基的计数结果显著优于国标培养基(P<0.05);凝结芽孢杆菌菌粉采用改良芽孢计数培养基计数结果优于PCA和NA计数培养基。结论:平板计数方法中,稀释液中含有酪蛋白胨能提升双歧杆菌菌粉的活菌计数数量;TOS琼脂培养基更有利于双歧杆菌的增殖培养;改良芽孢计数培养基更有利于凝结芽孢杆菌的芽孢萌发增殖。

Study on Quantitative Counting Method of Lactic Acid Bacteria Powder

Objective: On the basis of national standard GB 4789.35-2016, a comparative study was conducted on dilution ratio, diluent components and medium components to investigate the influence on the number of viable bacteria when counting lactic acid bacteria powder. Nine strains of Lactobacillus, six strains of Bifidobacterium, three strains of coccus and one strain of Bacillus coagulans were used as research objects. Methods: The method of dilution plate count was used to count the viable bacteria of different lactic acid bacteria powders. Results: According to research findings, the dilution ratio of the initial lactic acid bacteria powder sample had no significant effect on the final count of viable bacteria, and the ISO dilution had significant effects on the viable count results of some Lactobacillus and Bifidobacterium powders (P<0.05); The counting result of Bifidobacterium powder using TOS agar medium was better than that of national standard medium (P<0.05); The counting result of Bacillus coagulans powder using modified spore counting medium was better than PCA and NA counting culture base. Conclusion: The diluent containing casein peptone could increase the number of viable counts of Bifidobacterium powder when plate counting method was used; TOS agar medium was more conducive to the proliferation and culture of Bifidobacterium; The improved spore counting medium was more conducive to the spore germination and proliferation of Bacillus coagulans.