L-乳酸、D-乳酸对3种食源性致病菌的抑制作用

Antibacterial Activity of L-and D-Lactic Acid against Three Foodborne Pathogenic Bacteria

选用金黄色葡萄球菌（S.aureus）、大肠杆菌（E.coli ATCC 43889）、福氏志贺菌（Shigella flexneri CMCC 51334）3株常见的食源性致病菌,用于测定L-乳酸、D-乳酸的最小抑菌浓度（minimum inhibitory concentration,MIC）及最小杀菌浓度（minimum bactericidal concentration,MBC）,并比较L-乳酸、D-乳酸对3株食源性致病菌抑菌效果差异.结果表明：L-乳酸、D-乳酸对3株食源性致病菌均有不同程度的抑制作用,金黄色葡萄球菌MIC0.1 mg/mL、MBC 3.2 mg/mL,大肠杆菌MIC 0.1 mg/mL、MBC 1.6 mg/mL,福氏志贺菌MIC 0.1 mg/mL、MBC3.2mg/mL.在所选3株指示菌浓度105～106 CFU/mL、乳酸0.2 mg/mL质量浓度下,L-乳酸的抑菌效果显著高于D-乳酸.

Three common foodborne pathogenic bacteria, Staphylococcus aureus, Escherichia coli and Shigella flexneri, were selected for assessing the antibacterial activity of L- and D-lactic acid as indicated by minimum inhibitory concentration （MIC） and minimum bactericidal concentration （MBC）. The growth of all these foodborne pathogens was inhibited in the presence of L- or D-lactic acid. Both showed an MIC of 0.1 mg/mL for all the pathogens and an MBC of 3.2, 1.6 and 3.2 mg/mL for Staphylococcus aureus, Escherichia coli and Shigellaflexneri, respectively. L-lactic acid more significantly inhibited the three indicator strains at a density of 105-106 CFU/mL than its D-isomer when present at a concentration of 0.2 mg/mL.