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5种分离培养基对不同样品的分离效果比较 总被引:2,自引:0,他引:2
对目标菌和非目标菌在5种分离培养基的生长特性、生理生化特性进行测试,并分别对280份实验样品进行敏感性和特异性等方面的测试,根据测试结果来评价各个培养基对不同的样品中沙门氏菌的分离效果。实验结果显示,XLD分离培养基比较适合食品样品中沙门氏菌的分离;SS培养基比较适合粪便样品中沙门氏菌的分离;BS、DHL培养基对于2种样品的分离效果相当;而CAS分离培养基对于2种样品中沙门氏菌的敏感性和特异性均比较高,对于食品样品,特异性更高,对于粪便样品,其敏感性更高。提示在实际检测中应根据样品的性质选择分离培养基或者联合使用培养基,以提高实验的准确度和阳性检出率。 相似文献
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研究了各种增殖因子对双歧杆菌的增殖效果,选出几种增殖效果好、价格低的物质进行正交试验优化培养基.得出长双歧杆菌(PBA)增殖培养基:在基础培养基基础上额外按体积分数添加平菇汁20%、卷心菜汁20%、豆浆20%、胡萝卜汁5%.在此培养基中,PBA经16 h培养,菌数可达2.45×109CFU/mL;得出婴儿双歧杆菌(INF)增殖培养基:在基础培养基基础上额外按体积分数添加平菇汁10%,蕃茄汁15%,肝浸汁15%,在此培养基中INF经16 h培养,菌数可达2.58×109CFU/mL. 相似文献
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对添加单株双歧杆菌(分别为乳双歧杆菌BB12和长双歧杆菌BB536)的益生菌产品进行双歧杆菌计数实验.比较了在相同的稀释条件和培养条件下,倾注MRS、半胱氨酸盐酸盐+MRS(CYS-MRS)、BBL3种培养基,培养计数结果的差异.结果对添加乳双歧杆菌BB12的益生菌产品,3种培养基计数结果差异较显著(P<0.05),B... 相似文献
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选择性计数双歧杆菌培养基的效果比较 总被引:2,自引:0,他引:2
随着双歧杆菌基础研究和开发应用的迅速发展,双歧杆菌活菌计数方法越来越重要,实验目的是要选择1种适于选择性计数产品中双歧杆菌菌落数的培养基。主要采用菌落技术方法,比较了常用的8种选择性培养基对7种产品中双歧杆菌的选择性计数效果。结果表明,以改良MRS-X-Gal琼脂培养基上形成的双歧杆菌菌落数最高,且菌落特征明显,易于计数,是优选出的效果较好的选择性计数培养基。 相似文献
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蔬菜汁的乳酸菌发酵 总被引:2,自引:0,他引:2
为制备不含任何动物性来源成分的纯植物性的乳酸菌发酵产品,采用双歧乳杆菌、植物乳杆菌、保加利亚乳杆菌、嗜酸乳杆菌4种乳酸菌,在豆角、香菇、番茄、青瓜、胡萝卜和包菜6和蔬菜培养液中进行发酵。实验结果证明,4种乳酸菌可以在不添加其他营养物质的纯蔬菜培养液正常生长,但是不同菌种适合的蔬菜培养液也不相同,且混合蔬菜培养液培养效果要好于单一蔬菜培养液。番茄和青瓜混合培养液适合双歧乳杆菌生长,包菜和青瓜混合培养液适合植物乳杆菌生长,包菜和番茄混合培养液适合保加利亚乳杆菌生长,豆角和青瓜混合培养液适合嗜酸乳杆菌生长。蔬菜的乳酸菌发酵产品,在4℃下冷藏2周后,4种菌体的存活率均在106CFU/mL以上。在不添加其他营养物质的条件下,蔬菜汁可以用来生产活性乳酸菌产品,满足素食主义者、乳糖不耐症者的消费需求。 相似文献
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Probiotic lactic acid bacteria from Kung‐Som: isolation,screening, inhibition of pathogenic bacteria
Noraphat Hwanhlem Nisit Watthanasakphuban Siriporn Riebroy Soottawat Benjakul Aran H‐Kittikun Suppasil Maneerat 《International Journal of Food Science & Technology》2010,45(3):594-601
Lactic acid bacteria (LAB) were isolated from Kung‐Som at various fermentation periods. Only ten strains, named D2SM22, D6SM3, D6SM24, D6SM26, D8SM21, D10SM5, D10SM11, D10SM16, D10SM20 and D16SM26 showed a survival rate of more than 50% under the simulated gastric juice. After being subjected to simulated gastric juice, four strains (D6SM3, D8SM21, D10SM16 and D10SM20) showed a survival rate of more than 50% in simulated small intestinal juices. Growth of strain D6SM3, D8SM21 and D10SM16 under micro‐aerobic and anaerobic conditions was not different. Tested pathogenic strains (Escherichia coli, Staphylococcus aureus, Bacillus cereus, Vibrio parahaemolyticus and Salmonella sp.) were inhibited by probiotic LAB. However, none of strains could produce bacteriocins. All strains were identified as Lactobacillus plantarum. No differences in pH, acidity, LAB count and liking scores between Kung‐Som produced with starter culture and conventional method were observed (P > 0.01). 相似文献
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Invited review: methods for the screening, isolation, and characterization of exopolysaccharides produced by lactic acid bacteria 总被引:9,自引:0,他引:9
The ability to produce exopolysaccharides (EPS) is widespread among lactic acid bacteria (LAB), although the physiological role of these molecules has not been clearly established yet. Some EPS confer on LAB a "ropy" character that can be detected in cultures that form long strands when extended with an inoculation loop. When EPS are produced in situ during milk fermentation they can act as natural biothickeners, giving the product a suitable consistency, improving viscosity, and reducing syneresis. In addition, some of these EPS may have beneficial effects on human health. The increasing demand by consumers of novel dairy products requires a better understanding of the effect of EPS on existing products and, at the same time, the search for new EPS-producing strains with desirable properties. The use of genetically modified organisms capable of producing high levels of EPS or newly designed biopolymers is still very limited. Therefore, exploration of the biodiversity of wild LAB strains from natural ecological environments is currently the most suitable approach to search for the desired EPS-phenotype. The screening of ropy strains and the isolation and characterization of EPS responsible for this characteristic have led to the application over the past years of a wide variety of techniques. This review summarizes the available information on methods and procedures used for research on this topic. The information provided deals with methods for screening of EPS-producing LAB, detection of the ropy phenotype, and the physicochemical and structural characterization of these molecules, including parameters related to their viscosifying properties. To our knowledge, this is the first compilation of methods available for the study of EPS produced by LAB. 相似文献
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从啤酒生产所用的酵母菌中分离得到2株乳酸菌,经鉴定为短乳杆菌(Lactobacillusbrevis)和有害片球菌(Pediococcusdamnosus)。对这2株乳酸菌在麦汁中进行72h发酵产酸性能的实验,结果表明,该2株菌均使麦汁酸度上升0.6°T,因而会导致接种后的麦汁酸败。 相似文献
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从发酵马肉中分离纯化出7株乳酸菌,对它们的主要发酵特性如耐盐、耐硝,产黏液、产气等进行了测定,并比较了它们在不同温度下的生长和产酸情况以及发酵过程中的pH值的变化,发现其中3株乳酸菌具有较好的发酵特性,如生长快、产酸快,能够耐6%NaCl、耐150 mg/kg NaNO2,不产气、不产氨,H2O2实验、H2S实验、V-P反应均为阴性等,符合发酵肉制品生产菌种的要求. 相似文献
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为了筛选出具有抑制致病性大肠杆菌作用的乳酸菌,本实验以大肠杆菌ATCC25922作为指示菌,抑菌实验采用牛津杯法。通过发酵上清液对大肠杆菌ATCC25922的抑菌实验,初步筛选出三株乳酸菌发酵上清液对大肠杆菌ATCC25922具有抑制作用,经过对16S rRNA基因进行系统发育分析,发现这三株乳杆菌均为嗜酸乳杆菌。随后又对这三株嗜酸乳杆菌进行了耐酸、耐胆盐及抗生素敏感性实验。结果表明:KLDS1.0901酸耐受性最强,而KLDS1.0902和KLDS1.1003与Lactobacillus acidophilus NCFM酸耐受性接近;对照菌株Lactobacillus acidophilus NCFM胆盐耐受能力最强,KLDS1.0901和KLDS1.1003与Lactobacillus acidophilus NCFM胆盐耐受能力差异不显著,KLDS1.0902胆盐耐受能力最弱;对于抗生素敏感性,三株嗜酸乳杆菌展现出类似的结果,对氨基糖苷类的抗生素展现出耐受;相比于KLDS1.0902,KLDS1.0901和KLDS1.1003有着更好的益生作用潜能,因此随后将对这两株菌在细胞和动物模型中对抗病原菌的作用进行进一步的研究。 相似文献