Development of Leuconostoc lactis –Specific Quantitative PCR and its Application for Identification and Enumeration in Fermented Foods

Leuconostoc lactis plays a pivotal role in providing a pleasant aroma in fermented foods. In this study, an L. lactis -specific quantitative PCR (qPCR) method was developed by designing species-specific primers using comparative pan-genomic analysis to monitor the microbial populations during food fermentation. As a result, a hypothetical protein-encoding gene, Llac_03470 , was selected as a target gene to detect L. lactis using a designed set of primers (NlacF and NlacR). PCR analysis against genomic DNA of various lactic acid bacteria confirmed the specificity of the primers for the detection of genomic DNA of L. lactis strains. By using the primer set, a standard curve for qPCR analysis of L. lactis was established, and no significant differences ( p < 0.05) were found in the yields of the genomic DNA recovered from MRS medium and kimchi. In addition, the qPCR was validated to successfully enumerate L. lactis during kimchi fermentation. In conclusion, the newly developed qPCR method in this study can be used to detect L. lactis in fermented kimchi and to monitor the change in its population during the fermentation process.