Correlation between Cigar Maintenance Quality and Microorganisms Based on Molecular Ecological Network

To examine the potential impacts of key microbial taxa and their interactions on the sensory quality of cigar during maintenance, we analyzed the alterations in the microbial community and their intrinsic correlation with the chemical composition and sensory quality of cigars over a 32-day maintenance period, utilizing a combination of microbial high-throughput sequencing and molecular ecological networks. The results indicated that, relative to the pre-maintenance period (0 d), the Chao1 index and Shannon index of bacterial and fungal communities exhibited a declining tendency followed by an increase during the maintenance process, with the minimum value observed at 16 d. The composition of bacterial communities varied markedly across different time intervals; Staphylococcus had the highest relative abundance at the genus level, while Alternaria and Aspergillus were the predominant fungal species. Molecular ecological network and cohesion analyses indicated that the interrelations among microbial species in the post-maintenance period (32 d) grew more intricate, resulting in an expanded network size. Conversely, at 16 d, the network size diminished and exhibited reduced resilience to disturbances, attributable to a marked escalation in microbial community competition. Correlation analyses indicated that the advantageous genera linked to the enhancement of cigar quality were Staphylococcus, Aspergillus and Wallemia, whereas the detrimental genera related with the decline in cigar quality were Corynebacterium and Aerococcus. Structural equation modeling results indicated that enhanced microbial community interactions did not promote the enrichment of beneficial genera, and a competitive relationship existed between beneficial and detrimental genera during cigar maintenance.