丁香油与月桂酸对金黄色葡萄球菌的协同抑制作用

Synergistic Inhibitory Effect of Clove Oil and Lauric Acid on Staphylococcus aureus

摘要:

该研究探讨了丁香油、百里香油、薄荷油等三种植物精油以及中链脂肪酸月桂酸对金黄色葡萄球菌的抑制作用，筛选出具有协同抑制作用的组合丁香油与月桂酸，测定协同组合对金黄色葡萄球菌生长、细胞膜通透性的影响，并将该组合制成抑菌保鲜液，应用于生鲜米粉保鲜。结果表明，丁香油、薄荷油、百里香油及月桂酸对金黄色葡萄球菌的最小抑菌浓度分别为2.00 µg/mL、4.00 µg/mL、7.50 µg/mL以及9.00 µg/mL，丁香油和月桂酸联合使用，在浓度为1/4 MIC丁香油+1/4 MIC月桂酸时具有协同抑菌效果，此时分级抑菌浓度系数为0.50。丁香油与月桂酸协同处理使金黄色葡萄球菌细胞膜损伤，增加通透性。抑菌保鲜液对生鲜米粉中的菌落总数、金黄色葡萄球菌均有抑制作用，对维持生鲜米粉品质具有积极影响。72 h贮藏期间，处理组初始菌落总数比对照组至少低1.50 lg CFU/g；金黄色葡萄球菌降低1.65 lg CFU/g；酸度值比对照组至少低0.8 °T；感官评价得分均高于对照组。结果表明，丁香油与月桂酸协同组合制成抑菌保鲜液有可能成为生鲜米粉的可替代复合保鲜液。

Abstract:

The inhibitory effects of three plant essential oils, clove oil, thyme oil, peppermint oil, as well as medium-chain fatty acid, lauric acid, on Staphylococcus aureus were investigated. The combination of clove oil and lauric acid with a synergistic inhibitory effect on Staphylococcus aureus was selected. The effects of such a combination on the growth and cell membrane permeability of Staphylococcus aureus were studied. The combination was used to prepare an antimicrobial preservative solution, which was applied to preserve fresh rice noodles. The results showed that the minimum inhibitory concentrations of clove oil, peppermint oil, thyme oil and lauric acid against Staphylococcus aureus was 2.00 μg/mL, 4.00 μg/mL, 7.50 μg/mL and 9.00 μg/mL, respectively. The combined use of clove oil and lauric acid exhibited a synergistic antimicrobial effect when the concentration was 1/4 MIC clove oil + 1/4 MIC lauric acid, leading to a fractional inhibitory concentration index (FICI) of 0.50. The synergistic action of clove oil and lauric acid damaged the cell membrane of Staphylococcus aureus and increased the permeability. The antimicrobial preservative solution had inhibitory effects on the total plate counts and Staphylococcus aureus in the fresh rice noodles, and exerted a positive impact on maintaining the quality of fresh rice noodles. During the72-h storage, the treatment group had a lower initial total plate counts (by at least 1.50 lg CFU/g), smaller number of Staphylococcus aureus (by 1.65 lg CFU/g), lower acidity value (by at least 0.8 °T), compared with those of the control group; The sensory evaluation score of the treatment group was higher than that of the control group. The results showed that the antimicrobial preservative solution made by the combination of clove oil and lauric acid might be an alternative compound preservative solution for fresh rice noodles.