Zhao Lei, Zhang Dong, Liu Yang, Zhang Yi-Nan, Meng Dong-Qing, Xu Qiong, Zhong Jiang, Jiang Qiu-Yue, Zhao Yu, Wang Shi-Jie
Key Laboratory of Milk and Dairy Products Detection and Monitoring Technology for State Market Regulation, Shanghai Institute of Quality Inspection and Technical Research, Shanghai 200233, China.
Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China.
Foods. 2022 Jul 30;11(15):2282. doi: 10.3390/foods11152282.
Probiotics are universally recognized for their health benefits, despite the fact that their effects depend on the strain. Identification and enumeration of probiotic strains are required prior to evaluating their effectiveness. X253 is a potential probiotic strain with antioxidant capacity. Comparative genomics and single nucleotide polymorphisms (SNPs) were used to identify a strain-specific locus within the gene for strain X253 that was distinct in 30 different strains. Using quantitative PCR, the primers and probe designed for the locus were able to distinguish X253 from the other 20 probiotic strains. The chosen locus remained stable over 19 generations. The sensitivity of the assay was 0.2 pg genomic DNA of X253, or 10 cfu/mL bacteria of this strain. In terms of repeatability and reproducibility, relative standard deviations (RSD) were less than 1% and 3%, respectively. Additionally, this assay achieved accurate enumerations of X253 in spiked milk and complex powder samples. The strain-specific assay could be used for quality control and compliance assessment of dairy products.
益生菌因其对健康有益而得到广泛认可，尽管其效果取决于菌株。在评估益生菌菌株的有效性之前，需要对其进行鉴定和计数。X253是一种具有抗氧化能力的潜在益生菌菌株。通过比较基因组学和单核苷酸多态性（SNP）来鉴定X253菌株基因内的一个菌株特异性位点，该位点在30种不同菌株中是独特的。使用定量PCR，针对该位点设计的引物和探针能够将X253与其他20种益生菌菌株区分开来。所选位点在19代中保持稳定。该检测方法的灵敏度为0.2 pg X253基因组DNA，或该菌株10 cfu/mL细菌。在重复性和再现性方面，相对标准偏差（RSD）分别小于1%和3%。此外，该检测方法能够准确计数加标牛奶和复合粉末样品中的X253。这种菌株特异性检测方法可用于乳制品的质量控制和合规性评估。
