Rapid lactic acid bacteria identification in dairy products by high-resolution melt analysis of DGGE bands

Abstract

To investigate the application of high-resolution melt (HRM) analysis for rapid species-level identification of lactic acid bacteria (LAB) communities in dairy products, as well as for bacterial community profiling and monitoring. First, comparisons of HRM profiles of known reference strains of LAB and their denaturing gradient gel electrophoresis (DGGE) bands showed very good agreement, allowing species recognition and identification from DGGE bands by HRM. Second, samples of cheese, kefir grains and kefir were characterized by PCR-DGGE, and melting profiles of DGGE bands were compared with known reference strains. Of the 13 DGGE bands, ten were identified by HRM by comparison with the reference strains and only three required sequencing for identification. Use of HRM profiling for comparison and monitoring of total LAB communities from dairy products or starter cultures was also evaluated, and good agreement was found when comparing clustering of DGGE band profiles with clustering of HRM melting profiles. Identification of DGGE bands is possible by comparison of HRM melting profiles with known reference strains. HRM profiling is suggested as an additional approach for identification of DGGE bands.