Abstract: This study developed a real-time polymerase chain reaction (real-time PCR) method for the detection of Lactobacillus kefiranofaciens subsp. kefiranofaciens. Based on the 16S rDNA gene sequence and whole genome sequence of the type strain of L. kefiranofaciens subsp. kefiranofaciens ZW3, specific primers were designed and screened. The fluorescent dye SYBR Green I was used in the real-time PCR method. Its specificity, sensitivity and repeatability were evaluated, and this method was applied to detect several strains of this species and its mixtures with other lactic acid bacteria. The results showed that the proposed method was highly specific, sensitive and repeatable. The standard curve was linear with a determination coefficient (R2) of 0.965. Moreover, this method could specifically detect L. kefiranofaciens subsp. kefiranofaciens from its mixture with other lactic acid bacteria. In summary, the real-time PCR method could quickly and accurately detect L. kefiranofaciens subsp. kefiranofaciens, providing a new method for the specific qualitative and quantitative detection of L. kefiranofaciens subsp. kefiranofaciens.

Key words: Lactobacillus kefiranofaciens subsp. kefiranofaciens; real-time polymerase chain reaction; specific primers