From mountains to city: Tracking microbiota and aromas in salami fermentation

This study investigated the microbial, chemical, and metabolic dynamics of traditional Brazilian salami produced under different fermentation conditions to understand how processing environments and microbial activity shape product quality. Three treatments were evaluated: CAVA and CMD, relying on spontaneous fermentation at different altitudes, and STD, produced with a commercial starter culture. Physicochemical parameters (pH and water activity), microbial enumeration, volatile organic compounds (VOCs), metabolites (¹H NMR), and bacterial communities (16S rRNA) were monitored across four stages (0, 3, 17, and 31 days). Total aerobic counts increased from ∼5.3 log CFU/mL at day 0 to > 7.9 log CFU/mL at day 31, while lactic acid bacteria peaked at 8.1 log CFU/mL, highlighting robust fermentation dynamics. Enterobacteriaceae initially rose in CAVA (6.7 log CFU/mL) but decreased during ripening, indicating effective microbial suppression. VOC profiles shifted markedly, with significant accumulation of 2,3-butanediol, hexanal reduction, and increased 1-octen-3-ol and 2-pentylfuran during maturation. Metabolomic analysis revealed lactate as the dominant metabolite (>7500 μM at day 17), accompanied by rising acetate and glutamate levels linked to sensory development. PCA analysis confirmed a clear temporal separation of samples, reflecting structured metabolic progression. Spontaneous fermentation treatments exhibited greater variability but achieved final microbiological and chemical profiles comparable to those of the starter-culture process. These results demonstrate how fermentation strategy, microbial succession, and environmental conditions collectively shape the safety, aroma, and metabolic complexity of traditional salami, providing insights for improving artisanal meat production and linking product characteristics to geographical origin. • Salami produced at 1700 m and 900 m showed diverse bacterial communities. • L. sakei and S. equorum prevailed in semi-controlled salami (CMD) • CMD showed higher levels of esters and alcohols which are linked to intense aroma • Lower bacterial diversity in controlled salami (STD) impacting metabolite profile • 16S rRNA NMR, and GC-MS allowed understanding of microbial and chemical events