Influence of geographical origin and flour type on diversity of lactic acid bacteria in traditional Belgian sourdoughs

A culture based approach was used to investigate the diversity of lactic acid bacteria (LAB) in Belgian traditional sourdoughs and to assess the influence of flour type, bakery environment, geographical origin and technological charcteristics on the taxonomic composition of these LAB communities. For this purporse, a total of 714 LAB from 21 sourdoughs sampled at 11 artisan bakeries throughout Belgium were subjected to a polyphasic identification approach. The microbial composition of the traditional sourdoughs was characterized by bacteriological culture in combination with genotypic identification methods including repetitive element sequence-based PCR (rep PCR) fingerprinting and phenylalanyl-tRNA synthase (pheS) gene sequence analysis. LAB from Belgian sourdoughs belonged to the genera Lactobacillus, Pediococcus, Leuconostoc, Weissella and Enterococcus, with the heterofermentative species Lactobacillus paralimentarius, Lactobacillus sanfranciscensis, Lactobacillus plantarum and Lactobacillus pontis as the most frequently isolated taxa. Statistical analysis of the identification data indicated that the microbial composition of the sourdoughs is mainly affected by the bakery environment rather than the flour type (wheat, rye, spelt or a mixture of these) used. In conclusion, the polyphasic approach based on rapid genotypic screening and high resolution sequence dependent identification proved to be a powerful tool to study the LAB diversity in traditional fermented foods such as sourdough.