To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham, sensory attributes, physicochemical parameters, total volatile basic nitrogen (TVBN), microorganism community and biogenic amines of Rugao ham manufactured with different potassium lactate levels (0%, 0.5%, 1%, 2%) were investigated; the relationship between microbial community and the formation of TVBN and biogenic amines was further evaluated. With the increase of potassium lactate from 0% to 2%, the increased sensory scores and the decreased total aerobic bacterial count and TVBN were observed; the abundance of Staphylococcus increased, while the content of Halomonas decreased. LDA effect size (LEfSe) and correlations analysis showed that Staphylococcus equorum and Lactobacillus fermentum could be the key species to improve sensory scores and decrease biogenic amines and TVBN. Metabolic pathway analysis further showed that amino acids metabolism and nitrogen metabolism were mainly involved in decreasing TVBN and biogenic amines in the treatment of 2% potassium lactate.

To investigate the spoilage characteristics of Jinhua ham, sensory scores, volatile compounds, biogenic amine, physicochemical parameters and microbial counts were evaluated between normal and spoiled hams. The results showed that off-odors of spoiled hams were dominated by rancid, sour, sulfide and ammonia odors derived from these compounds including butanoic acid, methanethiol and dimethyl disulfide. Total content of biogenic amine in spoiled hams was significantly higher (more than 10-fold) compared with normal hams, and putrescine, cadaverine and histamine were the key components of biogenic amine of spoiled hams. Lower salt content, and higher moisture, TVB-N and thiobarbituric acid reactive substances (TBARS) values were observed in spoiled hams compared with normal hams. The populations of Enterobacteriaceae and Enterococcus of spoiled hams were obviously higher than that of normal hams. High moisture and low salt content caused the abnormal growth of Enterobacteriaceae and Enterococcus in spoiled hams, which contributed to the spoilage of Jinhua ham.