CO₂-assisted high pressure processing was termed as CO₂-HPP, and the inactivation of Escherichia coli and Staphylococcus aureus in liquid samples were treated by CO₂-HPP in this study. When CO₂ made up 20% of the total volume, it exhibited assisted inactivation of E. coli and S. aureus in phosphate buffered saline (PBS, pH 7.0) under HPP. Twenty percent CO₂-300 MPa/3 min induced 1.0 and 2.5 more log units reduction of E. coli and S. aureus than 300 MPa/3 min, respectively. Both mid-exponential and stationary phase cells of E. coli and S. aureus showed higher sensitivity to CO₂-HPP than HPP. However, the two microbes showed different inactivation behavior in real food of cucumber juice (pH 6.6) and apple juice (pH 4.3), and CO₂-HPP was more suitable for S. aureus than E. coli in the two juices. As compared with HPP, CO₂-HPP showed more severe damage on morphology and intracellular structure of E. coli and S. aureus cells through transmission electron microscopy (TEM), scanning electron microscopy (SEM), and flow cytometer microscopy (FCM), including appearance of collapsed cells, cell disruption, and more holes on cell membrane, membrane permeability, and strength of cytoplasm aggregation, which were probably due to the penetration, explosion, and acidification of CO₂ under HPP. The CO₂-assisted inactivation of bacteria subject to HPP has the potential application in food industry, especially for liquid food.

本研究将CO ₂辅助高压处理称为CO ₂ -HPP，并用CO ₂ -HPP处理液体样品中的大肠杆菌和金黄色葡萄球菌的失活。当CO ₂占总体积的20％时，它在HPP下在磷酸盐缓冲盐水（PBS，pH 7.0）中表现出大肠杆菌和金黄色葡萄球菌的辅助失活。20％的CO ₂ -300 MPa / 3分钟分别比300 MPa / 3分钟诱导大肠埃希菌和金黄色葡萄球菌减少1.0和2.5个log单位。大肠杆菌的中指数期和固定期细胞金黄色葡萄球菌和S.aureus对CO ₂ -HPP的敏感性高于HPP。然而，两种微生物在黄瓜汁（pH 6.6）和苹果汁（pH 4.3）的真实食物中表现出不同的灭活行为，并且在两种汁中，CO ₂ -HPP比大肠杆菌更适合金黄色葡萄球菌。与HPP相比，CO ₂ -HPP对大肠杆菌和金黄色葡萄球菌的形态和细胞内结构的破坏更为严重。细胞可以通过透射电子显微镜（TEM），扫描电子显微镜（SEM）和流式细胞仪显微镜（FCM）进行检查，包括塌陷的细胞外观，细胞破裂以及细胞膜上更多的孔，膜通透性和细胞质聚集强度，可能是由于HPP下CO ₂的渗透，爆炸和酸化。受HPP抑制的CO ₂辅助细菌的灭活在食品工业中具有潜在的应用，特别是在液态食品中。