Yongqi Tian,Yuanyuan Chen,Ruyang Huang,Tao Wang,Shaoyun Wang
Synergistic bacteriostatic action represents a potent strategy for combating microbial contamination in the food industry. This study investigated the synergistic bacteriostatic effect of epigallocatechin gallate (EGCG) and indole-3-carboxaldehyde (I3A). Results showed a pronounced synergistic action of EGCG and I3A against diverse food spoilage microorganisms, most notably Pseudomonas aeruginosa ( P. aeruginosa ), with a fractional inhibitory concentration index (FICI) of 0.25. Further research revealed that EGCG disrupted the cell wall and cell membrane of P. aeruginosa , while supplementing I3A significantly boosted the concentration of intracellular reactive oxygen species, thereby inflicting cellular damage. Moreover, the EGCG-I3A treatment inhibited the biofilm formation of P. aeruginosa in a dose-dependent manner, with the effectiveness increasing with the quantity of I3A added. Metabolomic study revealed a perturbation in glutathione and taurine metabolic pathways post synergistic treatment, compromising redox homeostasis. This synergistic treatment also downregulated uracil, proline, and glutamate metabolites, thereby suppressing Quorum Sensing (QS) and biofilm-associated expression within P. aeruginosa . Additionally, the combination significantly inhibited P. aeruginosa growth in fish meat. In essence, this study underscored the synergistic bacteriostatic efficacy of EGCG and I3A, highlighting its potential application in food preservation.
Qiuying Li,Chenyang Jia,Jiaxing Sun,Tong Sun,Jianrong Li,Xuepeng Li
The strong spoilage capability and cold adaptability of Shewanella putrefaciens present a serious threat to the quality and safety of fish. This study aimed to investigate the synergic antibacterial effects of six phenolic acids (Gallic acid, GA; Caffeic acid, CA; Protocatechuic acid; Ferulic acid; Chlorogenic acid; p-Coumaric acid) in pairs against S . putrefaciens , and to illustrate the antibacterial mechanisms. The fractional inhibitory concentration index (FICI) of 15 combinations of phenolic acids against S. putrefaciens ranged from 0.5-0.75, suggesting synergistic or partial synergistic antibacterial effects of these phenolic acids. Time-kill curves and morphologic observation demonstrated that GA and CA (GC) exhibited the strongest synergistic effect against S. putrefaciens . GC synergistically damaged the structure integrity of S. putrefaciens , leading to the leakage of intracellular substances and inhibiting the activity of Na + K + -ATPase and respiratory chain dehydrogenase. Both GA and CA could bind to DNA and cause changes in DNA content. Proteomics analysis revealed that 399 proteins were affected in the GC groups, a number significantly higher than that in the single GA and CA groups. GC inhibited dissimilatory nitrate and sulfate reduction, and enhanced fatty acid degradation and assimilatory sulfate reduction, which might cause the imbalance of energy supply and ROS accumulation. Meanwhile, the antioxidant-related enzymes, efflux systems and some two-components systems were upregulated, while chemotaxis were inhibited. GC synergistically inhibited S. putrefaciens in turbot, and retarded the spoilage process. The results revealed multi-targeted synergistic antibacterial mechanisms of GC against S. putrefaciens , suggesting GC might be a good strategy for controlling S. putrefaciens and fish spoilage.
危险品化学品经营许可证（带存储）