Integrated transcriptomic and metabolomic analyses reveal the antibacterial mechanism of whey fermentation powder against Bacillus cereus L18 and its efficacy in Liangpi preservation.

Abstract

Liangpi, a high-moisture and nutrient-rich wheat starch-based food, is prone to spoilage by spore-forming bacteria such as Bacillus cereus, presenting significant food safety risks. Whey fermentation powder (WFP) exhibits natural antibacterial properties and broad applicability, yet its mechanism for inhibiting Bacillus spp. remains unclear. This study employed integrated transcriptomic and metabolomic analyses to elucidate the antimicrobial mechanism of WFP against B. cereus L18, a starch-degrading strain isolated previously from Liangpi with notable amylolytic activity. WFP exhibited potent antibacterial activity, effectively inhibiting bacterial growth and inflicting substantial damage to cellular integrity. Multi-omics analyses revealed that WFP induces a multi-faceted antibacterial response: it triggers acute energy exhaustion by hyperactivating flagellar synthesis/assembly and cell wall synthesis/repair pathways, while simultaneously disrupting membrane integrity via interference with lipid metabolism. Concurrently, WFP provoked extensive metabolic dysregulation, characterized by perturbations in purine metabolism, restricted amino acid availability, suppression of the TCA cycle and oxidative phosphorylation, and aberrant activation of the pentose phosphate pathway. These collective disruptions led to critical failures in nucleotide, amino acid, and energy metabolism. Furthermore, key bacterial adaptive stress response pathways were significantly suppressed. Our findings demonstrate that WFP exerts its antibacterial effects through multiple synergistic mechanisms. In application studies, the addition of 0.10% WFP extended the shelf-life of fresh Liangpi by approximately 10 h without compromising its sensory properties. This research provides novel insights into strategies for controlling microbial spoilage in starch-based foods and offers a scientific foundation for optimizing industrial production and extending shelf-life.