A competitive quantitative polymerase chain reaction method for characterizing the population dynamics during kimchi fermentation.

The aim of this study was to develop a competitive quantitative-PCR (CQ-PCR) method for rapid analysis of the population dynamics of lactic acid bacteria (LAB) in kimchi. For this, whole chromosome sequences of Leuconostoc mesenteroides, Lactobacillus plantarum, and Lb. brevis were compared and species-specific PCR primers targeting dextransucrase, 16S rRNA, and surface layer protein D (SlpD) genes, respectively, were constructed. The tested strains were quantified both in medium and kimchi by CQ-PCR and the results were compared with the data obtained using a conventional plate-counting method. As a result, the three species were successfully detected and quantified by the indicated primer sets. Our results show that the CQ-PCR method targeting species-specific genes is suitable for rapid estimation of LAB population to be used in the food fermentation industry.