| Autor: |
Zhao L; 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., Zhang D; Junlebao Dairy Group, Shijiazhuang 050221, China., Liu Y; 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., Zhang YN; 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., Meng DQ; College of Life Sciences, Shanghai Normal University, Shanghai 200234, China., Xu Q; 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., Zhong J; Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China., Jiang QY; Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China., Zhao Y; College of Life Sciences, Shanghai Normal University, Shanghai 200234, China., Wang SJ; Junlebao Dairy Group, Shijiazhuang 050221, China. |
| Abstrakt: |
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. Lacticaseibacillus rhamnosus 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 holA gene for strain X253 that was distinct in 30 different L. rhamnosus strains. Using quantitative PCR, the primers and probe designed for the locus were able to distinguish L. rhamnosus 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 L. rhamnosus X253, or 10 3 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 L. rhamnosus X253 in spiked milk and complex powder samples. The strain-specific assay could be used for quality control and compliance assessment of dairy products. |
