A natural biopreservative: Antibacterial action and mechanisms of Chinese Litsea mollis Hemsl. extract against Escherichia coli DH5α and Salmonella spp

• Published in: Journal of dairy science 2019-11, Vol.102 (11), p.9663-9673
• Main Authors: Cai, XiaoTian, Wang, Xue, Chen, YiCun, Wang, YangDong, Song, DaFeng, Gu, Qing
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; antibacterial activity; chemical composition; Escherichia coli - drug effects; Food Preservatives - isolation & purification; Food Preservatives - pharmacology; Litsea - chemistry; Litsea mollis Hemsl. essential oil; mechanism of action; Microbial Sensitivity Tests; Oils, Volatile - pharmacology; Plant Extracts - pharmacology; Salmonella - drug effects
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2019-16292

Chemical preservatives have potential safety hazards, which may pose threats to human health. Safer biopreservatives are therefore urgently required. This study investigated the bacteriostatic activity and mechanism of Litsea mollis Hemsl. essential oil against Escherichia coli DH5α and Salmonella spp. Antibacterial activity of Litsea mollis Hemsl. essential oil 9 (LMEO9) against E. coli DH5α was observed (zone of inhibition was 5.0 ± 0.2 mm; minimum inhibitory concentration was 0.05%). Increases in electrolyte, nucleic acid, and alkaline phosphatase leakage in LMEO9-treated bacteria suggested that the cell envelope had been damaged. Scanning and transmission electron microscopy also demonstrated morphological alterations and content leakage during LMEO9 treatment. According to the kill-time analysis and propidium iodide uptake assay, LMEO9 led to cell death. These results demonstrated that LMEO9, which could affect bacterial cell envelope structural integrity, is a low-cost biopreservative that could be useful for the dairy industry and in fresh storage.