Effect of Vacuum Skin Packaging and High-Oxygen Modified Atmosphere Packaging on the Quality and Microbial Properties of Chilled Pork during Storage

This study analyzed the effect of vacuum skin packaging (VSP) and high-oxygen modified atmosphere packaging (HiOx-MAP) on the quality changes of pork during chilled storage (0-4 ℃ ), which were evaluated in terms of pH, color, total volatile basic nitrogen (TVB-N) content, thiobarbituric acid reactive substances (TBARS) value, protein carbonyl and sulfhydryl content, total viable count (TVC) and microbial diversity. The results showed that the brightness (L*) and yellowness (b*) values of pork were always higher in the HiOx-MAP group than those in the VSP group during the whole storage period (P < 0.05). Compared with the VSP group, the HiOx-MAP group showed a higher redness (a*) value at the early stage but a significant lower a* value at the late stage of storage (P < 0.05), indicating that the HiOx-MAP group had poor color stability. Furthermore, the HiOx-MAP group had higher TBARS value and lower protein carbonyl and sulfhydryl content (P < 0.05). Additionally, the shelf lives of both groups were 20-25 days, but the TVC of the HiOx-MAP group was significantly higher than that of the VSP group starting from day 10 (P < 0.05). With increasing storage time, the microbial diversity of both groups showed a decreasing trend, but the α diversity in terms of the number of operational taxonomic units (OTU), Chao1 index and Shannon index of the HiOx-MAP group was higher, indicating more abundant microbial species and diversity compared with the VSP group. When the TVC was close to the upper limit of the national standard, the dominant bacteria in the HiOx-MAP group were Leuconostoc, Serratia and Pseudomonas, while Carnobacterium was the dominant bacteria in the VSP group. In conclusion, HiOx-MAP is recommended to maintain better meat color for short-term storage (within 10 days), while VSP can be used for maintaining pork quality and extending the shelf life.