Abstract: This study aimed to establish an effective method for the prediction of the microbial spoilage of dry-cured ham. We compared the physicochemical characteristics of normal and spoiled Panxian hams. Meanwhile, we employed high-throughput sequencing and solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) to reveal the bacterial community structure and volatile flavor compounds of normal and spoiled hams, respectively. The results showed that low concentration of NaCl and high levels of water activity (aw), pH, and moisture were found in spoiled hams. Three members of the family Enterobacteriaceae, namely norank_Enterobacteriaceae, unclassified_Enterobacteriaceae, and Serratia, were determined as the predominant microorganisms in spoiled hams. Redundancy analysis (RDA) demonstrated that moisture and pH might be important factors influencing the two unknown strains of Enterobacteriaceae, and Serratia was closely related to NaCl content. The levels of ketones, hydrocarbons, benzene- and sulfur-containing volatile compounds in spoiled hams were higher than in normal hams. Linear discriminant analysis effect size (LEFSe) analysis indicated that phenol, phenylacetaldehyde, 1-pentadecene, dimethyl disulfide, and 3-methylbutyric acid were identified as characteristic volatile flavor compounds of spoiled hams. Network analysis between microorganisms and volatile flavor compounds illustrated that norank_Enterobacteriaceae and unclassified_Enterobacteriaceae were the main contributors to the volatile flavor compounds of spoiled hams. These findings provide a theoretical foundation for quality control of Panxian ham.

Key words: Panxian ham; deep spoilage; physicochemical characteristics; high-throughput sequencing; volatile flavor compounds; multivariate analysis