High-resolution GC × GC fingerprinting reveals atmosphere-dependent volatilome trajectories in pork spoilage.

The microbial spoilage of raw meat is modulated by the packaging atmosphere, yet the volatile fingerprints underlying these processes remain only partially resolved. This study establishes a structured volatilome fingerprinting workflow based on comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) to analyze pork spoilage under air, high-N2, and high-O2/CO2 packaging conditions. The applied approach achieved a more comprehensive and confident chemical characterization of the volatilome when compared to currently available results with conventional gas chromatography mass spectrometry (GC-MS) or real-time mass spectrometry. A total of 199 volatile organic compounds (VOCs) were detected, including numerous low-abundance and metabolically related compounds that were annotated by complementary orthogonal criteria. Multivariate analysis based on selected VOCs revealed atmosphere-specific volatilome trajectories and identified key spoilage markers including pyruvate-derived metabolites (acetoin, 2,3-butanedione, 2,3-butanediol), 3-methyl-1-butanol and several aldehydes and ketones. Overall, GC × GC provides enhanced chemical resolution and thus delivers new insights into raw pork spoilage mechanisms via uncovering additional trace-level metabolites not previously observed by other approaches. Expanding and rigorously annotating the meat volatilome would reinforce spoilage assessment and targeted preservation strategies, through resolving microbial metabolism and accurately discriminating spoilage trajectories.