Multi-Omics Analysis of Repair Mechanisms in Ohmic Heating–Induced Sublethally Injured Staphylococcus aureus: Integrating Lipidomics, Transcriptomics, and Proteomics with Applications in Milk and Vegetable Juice

Ohmic heating (OH) is a novel rapid heating technology that effectively control Staphylococcus aureus (S. aureus) survival. However, OH-induced sublethal injury to S. aureus pose risks to food safety and public health. Numerous studies have highlighted the importance of membrane repair for bacterial survival. Lipids are the main membranes components, however, their metabolic mechanisms after injured and repair are still unclear. In this study, we compared the lipid compositions of S. aureus in untreated, OH-injured, and end-repair states by non-targeted lipidomics and measured malondialdehyde (MDA) content changes, a lipid injury marker. Then, transcriptomic and parallel reaction monitoring analysis were conducted to examine the expression of lipid metabolism-related genes and key enzymes, respectively. The results revealed that OH treatment caused 53 differentially abundant lipids (DALs) increase, including CL, PG, PE, and Cer, while 83 DALs decreased. In the end-repair stage (repair for 5 h), 71 DALs decreased, while only 21 DALs increased. This phenomenon was also reflected in MDA concentration alternations, suggesting that OH-induced lipid homeostasis disruption and oxidative damage were alleviated upon repair. The overall changes trends of lipid biosynthesis enzyme were consistent with lipidomics. Notably, the general changes of lipids metabolism-related genes exhibited an opposite trend: decreased by OH treatment while partially restored after repair. These findings enhanced our understanding of lipid homeostasis in injured bacteria, provided theoretical support for inhibiting injured S. aureus repair in food, and promoting OH application in the food industry.