Occupational exposure to Baijiu fermentation environments alters nasal microbiota composition: a comparative analysis of Strong-flavor and Sesame-flavor production systems.

UNLABELLED: Traditional Chinese Baijiu fermentation environments harbor complex microbial consortia critical for product quality, yet their effects on human nasal microbiota remain poorly characterized. This cross-sectional study compared nasal microbiota profiles of Strong-flavor (n = 25) and Sesame-flavor (n = 22) Baijiu workers against non-exposed individuals (n = 30) using 16S rRNA sequencing of environmental samples and nasal swabs. After adjusting for age and working age, no significant differences in Shannon diversity or species richness were observed among the three groups (ANCOVA, P > 0.05). However, community structure differed significantly (PERMANOVA, marginal R² = 0.075, P = 0.001), with Strong-flavor workers clustering closer to non-exposed individuals than Sesame-flavor workers. FEAST-based source tracking identified entry-pit fermented grains, Daqu, and air as primary contributors, accounting for 18.63% and 21.39% of nasal microbiota in Strong- and Sesame-flavor workers, respectively. ALDEx2 revealed six genera depleted in both exposed groups (FDR < 0.05): Caproiciproducens, Petrimonas, Proteiniphilum, Sporosarcina, Syntrophomonas, and an uncultured genus. No genera were significantly enriched in either exposed group. These findings indicate occupational exposure to Baijiu fermentation environments reduces the nasal carriage of several anaerobic taxa without altering overall alpha diversity.

IMPORTANCE

This study is the first to systematically compare how two major Baijiu fermentation environments-Strong-flavor and Sesame-flavor-affect the nasal microbiota of workers. By integrating environmental and nasal microbiome data, we show that entry pit grains, Daqu, and air are the main known sources of bacteria found in workers' noses. Occupational exposure in both production systems depletes several anaerobic genera, while overall microbial diversity remains unchanged. These findings connect microbial ecology with occupational health and support practical interventions: improving Daqu storage and ventilation, routine microbial surveillance, and preserving traditional fermentation practices without compromising safety. This work advances our understanding of human environment microbial exchange in traditional food systems with implications for global fermentation industries.