College of Food Science, Shenyang Agricultural University, Shenyang, 110161, China.
Folia Microbiol (Praha). 2019 Nov;64(6):899-906. doi: 10.1007/s12223-019-00705-3. Epub 2019 Apr 16.
Lactobionic acid (LBA) is a newly identified natural polyhydroxy acid that is widely used in the food industry. In this study, the antibacterial effects and underlying mechanism of action of LBA against Staphylococcus aureus were investigated. LBA exhibited significant antibacterial activity against S. aureus with a determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 15 mg/mL and 50 mg/mL, respectively. The Growth curves indicated that LBA directly inhibited the growth of S. aureus. Moreover, LBA induced the leakage of alkaline phosphatase and nucleotides in the culture medium, indicating damage to the integrity of the S. aureus cell wall membrane, which was confirmed by transmission electron microscopy observations. The relative electric conductivity measurements indicated that LBA changed the cell membrane permeability. The preservation effect of LBA was evaluated by quantifying the total number of colonies, total volatile base nitrogen (TVB-N), and thiobarbituric acid reactive substances (TBARS). Overall, these results revealed that LBA exerts its antibacterial activity by breaking down the structure of the bacterial cell wall and membrane, thereby releasing the cellular contents as well as inhibiting protein synthesis, which ultimately lead to cell death. The total number of colonies, the TVB-N value, and the TBARS of cold fresh meat treated with preservatives were significantly lower than those of the control group (P < 0.05). With these antibacterial characteristics, LBA has potential to be used as a safe food additive in the food industry.
乳醛酸（LBA）是一种新发现的天然聚羟基酸，广泛应用于食品工业。本研究旨在探讨 LBA 对金黄色葡萄球菌的抗菌作用及其作用机制。LBA 对金黄色葡萄球菌表现出显著的抗菌活性，最低抑菌浓度（MIC）和最低杀菌浓度（MBC）分别为 15mg/mL 和 50mg/mL。生长曲线表明，LBA 直接抑制金黄色葡萄球菌的生长。此外，LBA 诱导培养基中碱性磷酸酶和核苷酸的泄漏，表明金黄色葡萄球菌细胞壁膜完整性受损，透射电子显微镜观察结果证实了这一点。相对电导率测量表明，LBA 改变了细胞膜的通透性。通过定量测定菌落总数、总挥发性碱基氮（TVB-N）和硫代巴比妥酸反应物（TBARS）来评估 LBA 的保鲜效果。总的来说，这些结果表明，LBA 通过破坏细菌细胞壁和细胞膜的结构来发挥其抗菌活性，从而释放细胞内容物并抑制蛋白质合成，最终导致细胞死亡。用防腐剂处理的冷鲜肉的菌落总数、TVB-N 值和 TBARS 值均显著低于对照组（P<0.05）。由于具有这些抗菌特性，LBA 有望在食品工业中作为一种安全的食品添加剂使用。
