Revealing quality deterioration mediated by representative spoilage microorganisms in processed duck by-products:...

Duck by-products are rich in high-quality proteins and lipids and represent valuable animal-derived food resources with considerable nutritional value. However, microbial spoilage during processing and storage remains a major challenge affecting the quality and safety of processed duck by-products (PDB). In this study, the predominant microorganisms in PDB were identified using high-throughput sequencing. Five representative isolates were isolated from spoiled PDB, including Paraclostridium benzoelyticum (two strains), Clostridium sporogenes, Enterococcus faecalis, and Proteus penneri. All isolates exhibited proteolytic activity, gas production ability, and different levels of heat resistance. Inoculation experiments showed that these strains significantly decreased pH and increased TVB-N and TBARS values in PDB within 24 h. GC-IMS analysis revealed a total of 33 volatile compounds, among which nine compounds (VIP > 1, P < 0.05), mainly aldehydes, alcohols, and esters, were identified as potential spoilage-associated volatile markers contributing to off-odor formation. Correlation analysis and hypothetical formation routes suggested that these off-odor compounds were mainly derived from amino acid degradation and lipid oxidation mediated by these strains. Overall, this study isolated and characterized five representative strains involved in volatile off-odor formation in PDB, providing valuable insights for microbial spoilage control and quality management.