Effect of Fermentation by Penicillium nalgiovense and Geotrichum candidum on the Flavor Characteristics and Microbial Community Structure of Mianning Hams

In this study, the effect of the use of Penicillium nalgiovense (M600) or Penicillium nalgiovense + Geotrichum candidum (M800) on the physicochemical, microbiological, and flavor substances taking place during the manufacture of Mianning ham, a traditional Chinese ham, was studied. Three groups of hams were created and analysed during the manufacturing process (samples were taken and analysed at 30, 90, 150, and 210 days). At the end of fermentation, a total of 178 flavor substances were identified in the three groups of fermented hams, including 30 aldehydes, 29 alcohols, 14 ketones, 23 esters, 14 acids, 53 hydrocarbons, and 15 other substances. Compared with the control group, aldehydes, esters, and hydrocarbons were significantly increased (p < 0.05), acids were significantly decreased (p < 0.05), and ketones were not significantly changed in the M600 and M800 groups. The control group had the greatest bacterial and fungal abundance at the end of fermentation, with a higher degree of uniformity in fungal composition. M800 group had the highest degree of uniformity in bacterial and fungal composition. In this study, the microbial community changes and volatile flavor substances during the fermentation of Mianning ham were investigated, and the key microorganisms in the fermentation process were analysed. The results of this study indicate that the addition of Penicillium nalgiovense and Geotrichum candidum is an effective strategy to improve ham flavor and enhance ham quality. The results of the study provided a basis for the industrial production of Mianning ham.