Li Liu,Yakun Guo,Weijia Zhang,Fan Bai,Jinlin Wang,Ruichang Gao,Xiaoming Jiang,Yuanhui Zhao,Xinxing Xu
This study proposed to investigate the inhibition mechanism of the Paenibacillus provencensis (PP-2) metabolites on the dominant spoilage bacteria of sea bass and the application in preservation. Shewanella (71.11 %) and Pseudomonas (13.54 %) were the main genera. The Shewanella putrefaciens (L-1) and Pseudomonas fragi (L-4) were isolated and purified based on spoilage factors as dominant spoilage bacteria. PP-2 supernatant metabolites at minimum inhibitory concentration (MIC, 150 mg/mL) inhibited L-1 and L-4 by more than 95 % with significant antioxidant properties. The PP-2 metabolites were detected by LC-MS mainly including organic acids and derivatives, lipids molecules, organic heterocyclic compounds, and organic oxides. According to the transmission electron microscope (TEM) results, Additionally, the metabolites demonstrated antioxidant properties and disrupted bacterial cell membranes, highlighting their potential for controlling seafood spoilage. PP-2 metabolites significantly lowered pH ( p < 0.05), TBARS values (0.33 ± 0.01 μmol/g), and TVB-N levels (24.06 ± 2.25 mg/100 g) compared to Nisin-treated and control groups after 6–8 d. After 8 d, colony counts in the PP-2 group (7.90 ± 0.01 log CFU/g) remained below the spoilage threshold. PP-2 metabolites also reduced protein oxidation, with carbonyl content at 0.33 ± 0.01 μmol/g and sulfhydryl content at 5.26 ± 0.18 μmol/g. The metabolites preserved textural properties, showing slower declines in hardness, elasticity, and chewiness, and lower juice leakage (9.37 ± 1.27 %). Metabolomic analysis revealed that PP-2 metabolites disrupted several key bacterial metabolic pathways, leading to bacterial death. These results suggest that PP-2 metabolites enhance seafood preservation by targeting bacterial metabolic processes.
Pseudomonas fragi is primarily responsible for the spoilage of various foods, especially meat. The aim of this study was to investigate the antibacterial mechanism of 3-carene against P. fragi . 3-Carene treatment decreased the phospholipid content and the fluidity of the cell membrane, induced reactive oxygen species (ROS) generation and affected respiratory chain dehydrogenase, oxoglutarate dehydrogenase and citrate synthase in P. fragi . Metabolomics and proteomics analyses further showed that in the presence of 3-carene, 519 proteins, 136 metabolites in positive ion mode and 100 metabolites in negative ion mode were differentially expressed. These proteins and metabolites were primarily involved in amino acid metabolism, fatty acid degradation, the tricarboxylic acid cycle (TCA cycle) and other processes. Consequently, the stimulation of 3-carene altered cell membrane properties, disturbed important amino acid and energy metabolism, and even caused oxidative stress. Additionally, the results of total viable counts and the total volatile base nitrogen indicated that 3-carene could significantly improve the preservation of refrigerated pork. This study suggested that 3-carene has promising potential to be developed as a food preservative.
危险品化学品经营许可证（带存储）