革兰氏阳性菌和阴性菌对山梨酸钾的耐受差异性

Study of the Tolerance Difference between Gram Positive and Gram Negative Bacteria to Potassium Sorbate

摘要:

对革兰氏阳性菌和革兰氏阴性菌对山梨酸钾防腐剂的耐受性差异进行了探讨。以食品中常见的革兰氏阳性菌(蜡样芽孢杆菌,金黄色葡萄球菌和单增李斯特菌)与革兰氏阴性菌(沙门氏菌、副溶血弧菌、荧光假单胞菌)为研究对象,针对纯培养状态和模拟食品体系进行了研究。结果显示,加入1g/L山梨酸钾后革兰氏阴性菌的菌数可减少近102～103.5 CFU/mL,而革兰氏阳性菌的菌数只能减少近10CFU/mL,说明山梨酸钾对革兰氏阴性菌的抑菌效果比革兰氏阳性菌要高2倍以上。最小抑菌浓度实验和即食海带的接种模拟实验结果与生长曲线结果相吻合,显示革兰氏阳性菌对山梨酸钾的耐受性强于革兰氏阴性菌,此结果对于今后应用山梨酸钾进行革兰氏阳性菌类的防控具有重要意义。

Abstract:

In this study,the tolerance of 3 gram positive(Bacillus cereus,Staphylococcus aureus and Listeria monocytologene) and 3 gram negative bacteria(Vibrio parahaemolyticus,Salmonella and Pseudomonas fluorescens) topotassium sorbate were carefully studied by pure cultivation and simulation of food system.When 1 g/L potassium sorbate was presented in culture,the number of gram negative bacteria was reduced to up to 2~3.5 lg(CFU/mL),while those of gram positive bacteria were only reduce to 1 lg(CFU/mL).This results demonstrated potassium sorbate inhibited on the gram negative bacteria growth than that of the gram negative bacteria.Results of pure culture,minimal inhibitory concentration(MIC) and inoculation to instant kelp results all showed that the tolerance of gram positive bacteria is better than gram negative bacteria.It may have significance in the application of potassium sorbate on the control of gram positive bacteria.