Abstract
Natural sourdoughs are commonly used in bread-making processes, especially for organic bread. Despiteits role in bread flavor and dough rise, the stability of the sourdough microbial community during andbetween bread-making processes is debated. We investigated the dynamics of lactic acid bacteria (LAB)and yeast communities in traditional organic sourdoughs of five French bakeries during the breadmakingprocess and several months apart using classical and molecular microbiology techniques. Sourdoughs were sampled at four steps of the bread-making process with repetition. The analysis of microbial density over 68 sourdough/dough samples revealed that both LAB and yeast counts changed along the bread-making process and between bread-making runs. The species composition was less variable. A total of six LAB and nine yeast species was identified from 520 and 1675 isolates, respectively. The dominant LAB species was Lactobacillus sanfranciscensis, found for all bakeries and each breadmaking run. The dominant yeast species changed only once between bread-making processes but differed between bakeries. They mostly belonged to the Kazachstania clade. Overall, this study highlights the change of population density within the bread-making process and between bread-making runs and the relative stability of the sourdough species community during bread-making process.