基于高氧包装牛肉中菌群结构和代谢特征的二氧化碳抑菌机制研究

冷却牛肉进行高氧气调包装时需要添加CO2来抑制微生物生长，进而减少肉品的腐败浪费。尽管现有CO2抑菌理论已被广泛接受，然而高氧包装中CO2对菌群组成及其代谢产物的影响尚不明确，CO2对细菌蛋白表达和代谢活动的干扰机制也亟待阐明，这些都与肉品腐败进程密切相关。针对以上问题，本课题拟在高氧包装牛肉贮藏过程中，利用高通量测序研究不同CO2浓度下的菌群演替过程，同时监测挥发性有机物等细菌代谢产物的变化规律，通过将这些变化与肉品感官评分及肉色指标进行回归分析和相关性分析，探讨CO2对肉品微生物腐败的抑制作用；为阐释贮藏后期特定菌群及腐败现象形成的内在原因，对特定腐败菌的胞内蛋白质组和代谢组进行联合分析，结合细菌数量及代谢产物变化，从细菌自身蛋白表达及代谢通路上揭示CO2的抑菌机制。本项目将进一步完善CO2的抑菌理论体系，为高氧包装冷却牛肉的微生物控制提供科学依据。

The high-oxygen modified atmosphere packaging (HiOx-MAP) of chilled beef requires the addition of CO2 to inhibit microbial growth and reduce meat waste caused by microbial spoilage. Although the existing bactericidal theory of CO2 has been widely accepted, the effect of CO2 on the bacterial community composition and bacterial metabolites in HiOx-MAP is still unclear, and the mechanism of CO2 interference with the intracellular protein expression and metabolic activity needs to be clarified, which are all closely related to the meat spoilage process. Based on the above issues, this study will explore bacterial successions by high-throughput sequencing, and monitor bacterial metabolite (e.g., volatile organic compounds et al.) changes during storage of HiOx-MAP chilled beef under different CO2 levels. Afterwards, the relationship between these changes and changes in sensory evaluation and meat color will be assessed through correlation and regression analysis, to investigate the CO2 inhibition on microbial spoilage. In order to explain the underlying causes of specific bacterial community and spoilage phenomena formations in the end of storage, the intracellular proteomic and metabolomic analysis of specific spoilage organisms, combined with the changes in bacterial counts and metabolites, will be also applied to reveal the bacteriostatic mechanism of CO2 from bacterial protein expressions and metabolic pathways. The new findings will complement the bacteriostatic theory system of CO2, and provide a scientific basis for the microbial control in HiOx-MAP chilled beef.