Mwangi Esther W, Shemesh Moshe, Rodov Victor
Institute of Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Institute, 68 HaMaccabim Road, P.O. Box 15159, Rishon LeZion 7505101, Israel.
Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel.
Foods. 2024 Oct 19;13(20):3322. doi: 10.3390/foods13203322.
The purpose of the present study was to investigate the mechanism of action of our newly developed green sanitizer formulation comprising a natural phenolic compound, gallic acid (GA), strengthened by the Generally Recognized as Safe (GRAS) materials hydrogen peroxide (HO) and DL-lactic acid (LA). Combining 8 mM GA with 1 mM HO resulted in an abundant generation of reactive oxygen species (ROS) and a bactericidal effect towards Gram-negative (, , and ) and Gram-positive () bacteria (4 to 8 log CFU mL reduction). However, the exposure to this dual formulation (DF) caused only a modest 0.7 log CFU mL reduction in the Gram-positive population. Amending the DF with 20 mM LA to yield a triple formulation (TF) resulted in the efficient synergistic control of proliferation without increasing ROS production. Despite the inability to grow on plates (>7 log CFU mL population reduction), the TF-exposed maintained high intracellular ATP pools and stable membrane integrity. The response of to TF could be qualified as a "viable but nonculturable" (VBNC) phenomenon, while with the other species tested this formulation caused cell death. This research system may offer a platform for exploring the VBNC phenomenon, a critical food safety topic.
本研究的目的是探究我们新开发的绿色消毒剂配方的作用机制，该配方包含一种天然酚类化合物没食子酸（GA），并由公认为安全（GRAS）的材料过氧化氢（HO）和DL-乳酸（LA）强化。将8 mM的GA与1 mM的HO混合会大量产生活性氧（ROS），并对革兰氏阴性菌（大肠杆菌、肠炎沙门氏菌和铜绿假单胞菌）和革兰氏阳性菌（金黄色葡萄球菌）产生杀菌作用（菌落形成单位减少4至8 log CFU/mL）。然而，暴露于这种二元配方（DF）仅使革兰氏阳性菌金黄色葡萄球菌的菌落形成单位适度减少0.7 log CFU/mL。用20 mM的LA对DF进行改良以产生三元配方（TF），可有效协同控制金黄色葡萄球菌的增殖，而不会增加ROS的产生。尽管无法在平板上生长（菌落形成单位减少>7 log CFU/mL），但暴露于TF的金黄色葡萄球菌仍保持较高的细胞内ATP池和稳定的膜完整性。金黄色葡萄球菌对TF的反应可被视为“活的但不可培养”（VBNC）现象，而对于其他测试的菌种，该配方会导致细胞死亡。这个研究系统可能为探索VBNC现象提供一个平台，这是一个关键的食品安全课题。
