Department of Food Science and Technology, Chungnam National University, Daejeon, 34134, Republic of Korea.
Department of Food Science and Technology, Chungnam National University, Daejeon, 34134, Republic of Korea.
Food Microbiol. 2019 Dec;84:103260. doi: 10.1016/j.fm.2019.103260. Epub 2019 Jul 5.
This study was conducted to investigate the antibacterial activity of the noni fruit extract (NFE) against Listeria monocytogenes (ATCC, 19111 and 19115) and assess its applicability for the washing of fresh-cut produce. Based on the results of the disc diffusion test, L. monocytogenes (ATCC, 19111 and 19115) was susceptible to the activity of NFE than other pathogens studied. Additionally, results of the time-kill assay indicated that NFE at a concentration of 0.5-0.7% effectively killed L. monocytogenes within 7 h. Furthermore, analysis of the intracellular components such as nucleic acids and proteins released from the bacterial cells and their SEM imaging revealed that NFE could increase the membrane permeability of cells resulting in their death. Compared to their unwashed samples, washing of romaine lettuce, spinach, and kale with 0.5% NFE gave a reduction of 1.47, 2.28, and 3.38 log CFU/g, respectively against L. monocytogenes (ATCC, 19111 and 19115), which is significantly different to that of NaOCl. A significant correlation was observed between the antibacterial effect induced due to NFE washing with the surface roughness of the fresh-cut produce than its surface hydrophobicity. Moreover, washing with NFE was not found to affect the color of the samples. These results indicated that NFE demonstrates good antibacterial activity against L. monocytogenes and can be used as a natural sanitizer to ensure the microbiological safety of fresh-cut produce.
本研究旨在探讨诺丽果提取物（NFE）对李斯特菌（ATCC19111 和 19115）的抗菌活性，并评估其在清洗新鲜切割农产品中的适用性。基于抑菌圈试验的结果，与研究的其他病原体相比，李斯特菌（ATCC19111 和 19115）对 NFE 的活性更敏感。此外，杀菌时间试验的结果表明，浓度为 0.5%-0.7%的 NFE 可在 7 小时内有效杀死李斯特菌。此外，对从细菌细胞中释放的细胞内成分（如核酸和蛋白质）的分析及其 SEM 成像表明，NFE 可以增加细胞的膜通透性，导致其死亡。与未清洗的样品相比，用 0.5%的 NFE 清洗生菜、菠菜和羽衣甘蓝，可使李斯特菌（ATCC19111 和 19115）分别减少 1.47、2.28 和 3.38 log CFU/g，与次氯酸钠的效果相比差异显著。NFE 清洗诱导的抗菌效果与新鲜切割农产品表面粗糙度之间存在显著相关性，而与表面疏水性的相关性则不显著。此外，用 NFE 清洗不会影响样品的颜色。这些结果表明，NFE 对李斯特菌具有良好的抗菌活性，可用作天然消毒剂，以确保新鲜切割农产品的微生物安全性。
