Profiling and Association of Microbiota and Volatile Compounds in Commercial Fermented Shrimp Pastes (Terasi)

Terasi, or fermented shrimp paste, is a staple condiment in Indonesian cuisine, produced through spontaneous fermentation of small crustaceans under high-salt conditions. Despite its widespread culinary use, comprehensive studies examining both the microbiota and volatile compounds in commercial terasi remain scarce. This study aimed to characterize the microbial composition and volatile profiles of ten commercial terasi products sourced from different regions of Indonesia, representing both traditional home industries and large-scale manufacturers. Culture-dependent microbial enumeration and 16S rRNA gene sequencing were employed to assess microbial diversity, while volatile compounds were identified and quantified using gas chromatography-mass spectrometry (GC-MS). Results revealed significant differences in microbial load and community composition among samples, with traditional products showing higher viable counts and microbial diversity, dominated by genera such as Tetragenococcus, Bacillus, Weissella, and Halanaerobium. Industrial samples, by contrast, contained no detectable microorganisms, likely due to sterilization practices for extended shelf life. A wide range of volatiles, including sulfur compounds, short-chain fatty acids, and trimethylamine, were identified across all samples, with a total of 48 detected compounds. Notably, correlation analysis revealed strong associations between specific bacterial genera and key volatile compounds, suggesting that microbial activity plays a central role in shaping terasi's flavor. This integrative analysis provides new insights into the microbial-chemical interactions underlying fermented shrimp paste and offers potential applications for product standardization, starter culture development, and culinary innovation.