发酵牛肉调味基料对三株致病菌的抑菌作用及机理

为了研究发酵牛肉调味基料(Fermented Beef Flavorings,FBF)的抑菌作用和抑菌机理,试验采用WBL-45(木糖葡萄球菌+肉葡萄球菌+清酒乳杆菌)、VHI-41(木糖葡萄球菌+戊糖片球菌+植物乳杆菌)、清酒乳杆菌(Lactobacillus sake,LS)为发酵剂,将牛骨肉末高压浸提、酶解、发酵、美拉德反应后制作FBF,以大肠杆菌、乙型副伤寒沙门氏菌、金黄色葡萄球菌为指示菌,应用光密度法研究不同处理组FBF对三株致病菌的半数抑制浓度(Inhibitory Concentration 50,IC₅₀),同时研究FBF处理后指示菌的生长曲线,以此来评价三组FBF的抑菌作用;通过扫描电镜观察菌体形态,测定相对电导率了解胞膜通透性,阐述FBF的抑菌机理。结果表明:WBL-45组对大肠杆菌、乙型副伤寒沙门氏菌、金黄色葡萄球菌的IC₅₀浓度依次为3.75、7.5、3.75 mL/100 mL,VHI-41组和LS组FBF对三株指示菌IC₅₀浓度依次为3.75、3.75、1.88 mL/100 mL。FBF能够抑制三株指示菌的正常生长和增殖,延长延滞期,降低指示菌最大比生长速率以及稳定期的菌量,破坏细胞的正常形态,使菌体表面出现褶皱、孔洞,影响菌体营养物质的正常传递和运输,从而抑制指示菌生长。

Inhibitory Effect and Mechanism of Fermented Beef Flavorings on Three Pathogenic Bacteria

The bacteriostasis and bacteriostasis mechanism of fermented beef flavorings(FBF)were studied. In the experiment,WBL-45(Staphylococcus xylose+Staphylococcus bovis+Lactobacillus sake),VHI-41(Staphylococcus xylose+Staphylococcus pentosus+Lactobacillus plantarum),Lactobacillus sake(LS)were used as starters to prepare FBF after high-pressure extraction,enzymolysis,fermentation and Maillard reaction of bovine bone and meat powder,Escherichia coli,Salmonella paratyphoid B and Staphylococcus aureus were the target bacteria. The inhibition concentration 50(IC₅₀)of FBF on three pathogenic bacteria in different treatment groups was studied by optical density method. The growth curve of target bacteria after FBF treatment was studied,the bacteriostatic effect of three groups of FBF was evaluated. The morphology of bacteria was observed by scanning electron microscope,and the relative conductivity was measured to understand the permeability of cell membrane. The bacteriostatic mechanism of FBF was expounded. The results showed that the IC₅₀ of E. coli,Salmonella paratyphi B and Staphylococcus aureus in WBL-45 group were 3.75,7.5,3.75 mL/100 mL,respectively. The IC₅₀ of FBF in VHI-41 group and LS group were 3.75,3.75,1.88 mL/100 mL respectively. The normal growth and proliferation of the three indicator bacteria were inhibited,the delayed period was prolonged,the maximum specific growth rate and the amount of bacteria in the stable period were reduced,the normal morphology of the bacteria was destroyed by FBF,and the surface of the bacteria was folded and holes,normal transmission and transport of nutrients in the bacteria were affected,so that the growth of the indicator bacteria was inhibited.