Traceability Analysis between Strong-Flavor Daqu, a Traditional Chinese Fermentation Starter for Nongxiangxing Baijiu, and Microbial Communities in the Production Environment

To uncover the origin of the microbial community in strong-flavor Daqu, this study investigated the traceability of the microbial communities in Daqu and environmental samples from old and new production bases of one distillery. The production environment was thought to play a key role in the manufacturing process of Daqu. The results of SourceTracker showed that the major microbial sources of the raw starter brick before incubation from the old base were the raw materials and the production tools, and the environment in the old base contributed more to the bacterial communities in the raw starter brick and mature Daqu (Daqu just transferred to the storeroom). However, the fungal community was relatively stable and less affected by the environmental microbiota. As powdered aged Daqu (above three months old) was used to improve the quality of fresh Daqu, the microbial sources of the raw starter brick and mature Daqu from the new production base were the aged Daqu. A suitable environment for the production of Daqu could be created by proper fortification methods, which is of great significance to maintain the quality of Daqu.