Linking microbial diversity and volatile compounds in Pecorino cheeses

Microbial communities shape the distinctive aroma of Pecorino cheeses through the production of volatile organic compounds (VOCs), yet these microbiome–VOC interactions remain poorly understood. We characterized the microbiome and VOCs of 37 samples across seven Italian Pecorino types. Firmicutes dominated (96.9%), with Streptococcus thermophilus and Lactococcus lactis as core species. Notably, Actinobacteria showed marked cheese-specific enrichment (up to 75.7% in Pecorino Bagnolese), strongly associated with branched-chain volatile compounds derived from amino acid catabolism. Volatile acids were the predominant class, followed by ketones and esters. Linear Discriminant Analysis clearly discriminated cheese types, with ethyl hexanoate, ethyl butanoate, and 2-hexanone as key markers. Correlation network analyses revealed cheese-specific bacteria–VOC association patterns, ranging from dense networks in Bagnolese to sparse networks in other types. These findings highlight microbial terroir as a driver of Pecorino VOCs and provide insights into microbial–chemical interactions underlying aroma development, with potential implications for cheese typicity and quality control.