不同来源乳酸菌胞产物对两种致病菌抑制研究11.docVIP

不同来源乳酸菌胞外产物对两种致病菌抑制研究 唐雨顺 李君君 摘要 本试验研究了乳酸菌胞外产物对鸡致病性大肠杆菌和鸡致病性沙门氏菌的体外抑菌作用，同时MRS对照液作为空白。研究热处理、酶处理、pH处理后对乳酸菌胞外产物的影响，观察处理后的实验组对鸡致病性大肠杆菌和鸡致病性沙门氏菌的作用效果。结果表明，乳酸菌胞外产物的pH为3.9，pH处理对乳酸菌胞外产物有明显影响，pH越低，乳酸菌胞外产物对致病菌的抑制作用越强。乳酸菌胞外产物对热处理不敏感，经热处理的乳酸菌胞外产物具有良好的热稳定性、良好的抗蛋白酶性和抗过氧化酶性。乳酸菌体外培养后的无菌上清液有较强的抑菌活性。 关键词：乳酸菌；乳酸菌胞外产物；鸡致病性大肠杆菌；鸡致病性沙门氏菌；体外抑菌试验 Inhibitory Effects of Lactobacillus′sExtracellular Products from Different Originson 2 Kinds of Pathogenic Bacteria Abstract Lactobacillus′s extracellular products were used to study growth inhibition of pathogenic E.coli of chicken and pathogenic salmonella of chicken, while MRS medium become the control. To research the impacts of Lactobacillus′s extracellular products after heating, enzymatic and pH treatment and the effects of the experimental group on pathogenic E.coli of chicken and pathogenic salmonella of chicken. The results showed that pH value of Lactobacillus was 3.9, pH treatment has a obvious influence on inhibitory ability of Lactobacillus metabolites: the lower pH value, the stronger inhibitory ability was. Lactobacillus′s extracellular products is not sensitive to heat, so Lactobacillus′s extracellular products exhibited a good thermal stability, anti-protease activity and antioxidant enzymes activity. The results also indicated that the supernatant of Lactobacillus had significant restraining effects on pathogenic E.coli． Key words: Lactobacillus；extracellular product of Lactobacillus；pathogenic Ecoli of chicken；pathogenic salmonella of chicken；growth inhibition of Ecoli 前　言 酸乳是一个历史悠久的产品,被古代伊斯兰教徒称做约古特(Yoghurt)。早在20世纪初，诺贝尔生理学与医学奖获得者、俄国著名科学家梅奇尼科夫就注意到经常食用酸乳的巴尔干国家的居民寿命较长，提出了“酸乳长寿说”。在国内外也有对乳酸菌的深入研究，如Baird（1977）用乳酸菌饲喂断奶仔猪和生长育肥猪，试验证明均能增加日增重和提高饲料转化率；Lidbeck等人（1992）证实乳酸菌能预防放疗引起的腹泻；Gallagher等人（1974）研究表明食用酸奶的人群对乳糖的利用率比食用含相同乳糖浓度的牛奶要高，从而减轻乳糖的不耐受症状。此外，乳酸菌的抗癌作用也有不少报道。 乳酸菌饮料是酸乳类的产品，自上世纪80年代我国即有乳酸菌饮料的生产。乳酸菌饮料深受广大消费者的喜爱，而随着技术的进步，特别是优良、安全的发酵菌种的采用迅速成为乳制品工业发展最快的产品之一。2003年全球的发酵乳饮料市场增长了9.3％，大大超过了其他乳制品的增长率。乳酸菌饮料销售收入的增长除了在它传统的亚太地区获得成功之外，在西欧、拉美市场上的渗