实时荧光PCR方法快速检测鉴定啤酒有害菌的研究

本文对PCR方法快速检测鉴定啤酒有害菌进行了研究,结果表明使用实时荧光PCR方法检测啤酒有害菌可以将检测时间缩短至48h,并可以同时得到检测与鉴定的结果。该方法有较好的特异性、可重复性,相比传统培养基法,PCR法的检测结果准确可靠。     

XGAL-MUG法：饮用水中大肠菌群检测的新方法

大肠菌群是影响饮用水安全的主要因素之一,其检测方法的使用非常重要。为了方便用户对检测方法的选用,本文将传统的LB-BGLB培养基法（简称LB法）、MMO-MUG法（简称MMO法）、XGAL-MUG法（简称XGAL法）进行了比较。LB法和MMO法都是已被官方采用的方法：XGAL法是采用安科生物制品（上海）有限公司开发的一种显色培养基进行检测的方法。     

应用干制培养基检测食品中金黄色葡萄球菌

目的建立金黄色葡萄球菌X干制培养基(Staphylococcus aureus X medium, XSA)检测食品中金黄色葡萄球菌的分析方法。方法依据GB 4789.10—2016《食品安全国家标准食品微生物学检验金黄色葡萄球菌检验》中前处理的方法制备样品,将样品添加到7.5%NaCl肉汤增菌后接种至干制培养基XSA上进行培养,通过鉴定实验进行定性检测和菌落平板计数进行定量检测,并用国标法同时进行定性及定量检测。结果在定性检测方面,该方法和国标方法假阴性率和假阳性率均为0%,但是检测时间由92 h缩短为48 h,在定量检测方面,该方法与国标法的对数偏差值的绝对值为0.3979<0.45,并且在6次检测同一个样品时的结果相对标准偏差较小,从而说明该方法和国标法的准确度相当,检测时长由78h缩短至24h,大大提高了检验效率。结论该方法操作简便快捷,结果稳定,适用于食品中金黄色葡萄球菌的检测。     

评价平板法定量检测单增李斯特氏菌

目的 评价平板法定量检测单增李斯特氏菌的效果以保障其准确性和灵敏性。方法 选择市场上常用的5种显色培养基和PALCAM琼脂培养基进行试验,根据4789.28-2013对培养基的质量和效果进行评估;依据GB 4789.30-2016进行单增李斯特氏菌平板计数,通过配对t检验法对6种培养基定量结果进行分析,同时比较涂布法和倾注法两种接种方法的差异性。结果 市售的6种培养基半定量测试中,目标菌的生长指数G＞6,非目标菌的生长指数G＜1,质量符合标准检测要求;统计分析显示6种培养基获得的单增李斯特氏菌计数结果无显著差异,但显色培养基的上菌落分布均匀,容易辨认,效果优于PALCAM;同时过分析两种接种方法的检测结果,发现涂布法和倾注法无显著性差异。结论 市售的6种培养基质量符合标准要求,且对单增李斯特氏菌的计数结果具有较好的一致性,涂布法和倾注法两种接种方法具有可交换性。     

食品中肌醇的微生物检测方法研究

目的:建立测定食品中肌醇含量的微生物方法。方法:利用肌醇缺陷型菌种在不含肌醇培养基中的生长与肌醇浓度呈正相关的原理,对选取的葡萄汁酵母菌和酿酒酵母菌各三株进行筛选,并对目的菌株的培养基进行选择,采用四参数Logistic曲线拟合,根据吸光度计算出食品中肌醇的含量,并对此法进行了方法学验证。结果:筛选出肌醇缺陷型菌种葡萄汁酵母菌CICC 1465,使用市售青岛日水肌醇测定用培养基进行实验。该法检测肌醇的曲线范围为0.1～1.0μg/m L,强化食品与天然食品的精密度、重复性良好,回收率在90%～110%之间,检出限为0.375 mg/100 g。结论:该方法能够准确检测强化食品与天然食品中的肌醇含量,为食品安全国家标准中优化检测肌醇的微生物方法提供有效的参考。     

鸡肉中弯曲菌定量检测方法的建立与初步应用

目的参照国标方法,建立鸡肉中弯曲菌定量检测的CCDA平板计数法。方法通过对选择性CCDA培养基中添加不同浓度组合的抗生素和生长促进剂,确定最佳添加浓度组合,并与普通CCDA平板计数法进行比较,建立鸡肉中弯曲菌定量检测方法,同时评价该方法的特异性和检测限。结果添加一定浓度抗生素和生长促进剂的选择性CCDA培养基和普通CCDA培养基对弯曲菌标准菌株定量计数的吻合度为(100±5)%;除弯曲菌外,其他5种肠道细菌在该CCDA培养基中均不能生长;该方法对弯曲菌菌悬液可检测至10 CFU/mL。运用该方法对50份鸡肉样品进行调查研究,共检测出22份阳性样品,弯曲菌检出率为44%,平均检测值为20CFU/100 cm~2,检测结果与国标方法阳性符合率为100%。结论该方法简便、特异性好、准确度高,为定量检测鸡肉中弯曲菌提供了新技术。     

一种改进的产生物胺乳酸菌的检测方法

本文自行设计了一种对产生物胺(BA)乳酸菌进行检测的双层培养基法，利用该方法对实验室保藏菌种和一些发酵食品中的菌株进行了检测，实验证明此方法可在同一块平板上区分开产生物胺菌和不产生物胺菌，且方法简单、易于识别、准确性高，对生产和优良菌种发酵剂的开发很有帮助。     

应用测试片快速检测食品中金黄色葡萄球菌的研究

采用法国进口的金黄色葡萄球菌显色培养基为主要原料,运用微生物测试片专有技术将其制成一次性的快速测试片.经测试,该测试片的检测灵敏度高,特异性强,重复性好.其对纯菌的检测下限可达3 cfu/mL.与营养琼脂计数、Baird-Parker培养基计数和显色培养基计数比较,检测结果均无显著性差异(P>0.05).对染菌样品的检测结果.测试片与3MTMPetrifilm法无显著性差异(P>0.05),而检测下限明显低于GB标准方法.     

培养温度和培养基对生鲜奶菌落总数快速测定的影响

研究了培养温度和培养基对阻抗法快速检测生鲜奶菌落总数的影响。结果表明，采用阻抗测定培养温度30℃、MPCA培养基可实现对生鲜奶菌落总数的快速检测。与传统方法相比，采用阻抗法进行生鲜奶中菌落总数的测定具有快速、简便、准确的特点．不合格样品检验周期少于7h。     

小肠结肠炎耶尔森菌前增菌方式的选择

小肠结肠炎耶尔森菌作为一种食源性致病菌逐渐引起了关注。本实验利用胰蛋白胨培养基、改良磷酸盐缓冲液和氯苯酚-替卡西林-氯酸钾培养基对小肠结肠炎耶尔森菌前增菌,并采用实时荧光PCR方法对增菌效果进行检验。结果表明：在纯菌体系中胰蛋白胨培养基对小肠结肠炎耶尔森菌的增菌作用优于其他两种培养基,并且增菌24h后即可检测到该菌。在混菌体系中小肠结肠炎耶尔森菌经过改良磷酸盐缓冲液增菌后灵敏性最高,并且增菌时间可缩短至8h。因此在实际检测中可采用改良磷酸盐缓冲液对该菌进行增菌检测。     

保加利亚乳杆菌菊芋复合汁增菌培养基的优化筛选

以菊芋为主要原料,以自行分离选育的高活力保加利亚乳杆菌(Lactobacillus bulgaricus)L.b-DR为试验菌株,研究了在菊芋汁培养基中添加单一营养因子对保加利亚乳杆菌L.b-DR细胞生长量的影响;利用正交试验优化筛选出保加利亚乳杆菌L.b-DR的菊芋复合汁增菌培养基。试验结果表明:在菊芋汁基础培养基中添加番茄汁、乳糖、蛋白胨、碳酸钙,可显著促进试验菌株的细胞生长(P<0.01);利用L934正交试验筛选出菊芋复合汁增菌培养基的最佳配比是:在菊芋汁培养基中添加7.5%番茄汁,1.5%乳糖,1%蛋白胨,0.3%碳酸钙。保加利亚乳杆菌L.b-DR经过复原脱脂乳培养基和液体MRS培养基活化后,以1%(约1×106cfu/mL)接入菊芋汁复合增菌培养基中,37℃培养16h,活菌数可达1.50×109cfu/mL,较对照菊芋汁培养基的活菌数提高23.96倍,与实验室常用的MRS培养基的活菌数相当,而其成本较实验室常用的液体MRS培养基的成本降低了2400元/t。     

DPS数据处理软件在发酵培养基优化中的应用

在发酵工业中,发酵培养基的优化对发酵水平的提高具有非常重要的作用。DPS(Data Processing System)是一款强有力的数据处理软件,兼具多种类型的试验设计技术以及齐全的统计分析功能。文中介绍了DPS数据处理软件在发酵培养基优化中的具体实施方法和步骤,运用该软件对试验结果进行处理,结果表明,DPS数据处理软件能简单且有效地对发酵培养基进行优化。     

PRODUCTION OF STEROID GLYCOALKALOIDS BY PHYTOPHTHORA INFESTANS IN COMPLEX AND CHEMICALLY DEFINED MEDIA

A chemically defined synthetic medium was developed on which Phytophthora infestans (Mont.) de Bary strain 1.2.4 grew extensively. The medium consisted of: 90.0 g maltose; 20.0 g L-proline; 20.0 g DL-alanine; 1.0 g KNO₃; 0.50 g KH₂PO₄; 0.25 g MgSO₄ 7H₂O; and 1.0 mg thiamin per liter of distilled water. The average level of growth on this medium was 0.5864 g dry weight mycelium per 50 ml medium. The glycoalkaloids, solanidine and solanine, were produced by P. infestans in this medium at an average concentration of 0.8518 mg total glycoalkaloids per 25 ml medium with a range of 0.0 to 5.9 mg per 25 ml. No glycoalkaloid production was detected when the level of growth of the fungus was below 0.35 g dry weight mycelium/50 ml medium. Glycoalkaloids were synthesized by 5 of 10 cultures grown on chick pea medium and by none of 10 cultures grown on rye seed medium.     

酵母内海藻糖积累条件的优化

对面包酵母 (BY 11)海藻糖积累条件进行了较系统的研究 ,采用了PB和响应曲面设计法 ,得到了 1个优化的培养基。采用此培养基 ,以 3 g/L(以酵母干固物计 )的接种量 ,3 7℃震荡培养 3h可积累海藻糖 0 96g/L ,从而大大提高了海藻糖的产量 ,为工业生产提供了可行性。     

Rapid routine method for the detection of lactic acid bacteria among competitive flora

The modified CHALMERS medium, developed by our laboratory, was compared with other selective commercial media to enumerate the total number of lactic acid bacteria in fermented dairy and meat products. This new medium was the only one which permitted the distinction of lactin acid bacteria due to the characteristics of their colonies among competitive gram-positive flora on one plate only. Its confirmation rate for suspected lactic acid bacteria colonies was found to be 100%. The productivity of the medium was comparable to that found for other media and gave the best results for both the selectivity and the standard deviation of the counts, especially in fermented meat products. As the lactic acid bacteria are easily distinguishable by characteristic colony types with this medium, additional confirmatory tests are not necessary. Therefore this new eletive medium can be used as a rapid cheap method for detection of lactic acid bacteria in any food, where they are either as ‘starters’ or as contaminants.     

利用选择性培养基快速初步鉴定食品中的致病微生物

目的 建立快速区分鉴别某种(类)微生物的方法。方法 选择几种常用的培养基, 将不同的菌株接种在培养基上, 通过培养基成分对不同微生物的选择性、显色反应及不同菌株在选择性培养基上具有的特征性菌落形态, 初步并快速判定微生物, 尤其是致病类微生物。结果 大肠埃希氏菌会与其他致病菌混淆, 可以通过结晶紫中性红胆盐(crystal violet neutral red bile salt, VRBA)琼脂将其区分; 志贺氏菌在培养基上菌落基本均为半透明, 体现的均为培养基本身的颜色; 亚硫酸铋(sulfurous acid bismuth, BS)琼脂的选择性较强, 但鼠伤寒沙门氏菌在该培养基上长势良好。结论 该方法可有效提高鉴别致病菌的效率。     

Phenolic colorants obtained by enzymatic synthesis using a fungal laccase in a hydro-organic biphasic system

The oxidation of ferulic acid by laccase from Myceliophthora thermophila was followed with high performance liquid chromatography (HPLC) in aqueous and hydro-organic medium. Results achieved in this study showed that the enzymatic activity and the stability of the products greatly varied depending on the nature of the reaction medium.The oxidation of ferulic acid in a biphasic hydro-organic system (perfectly mixed) consisting of ethyl acetate and sodium–phosphate buffer resulted in intermediate stable yellow products. The organic solvent which decreased the activity of the laccase and the rate of non-enzymatic reactions led to the stability of these intermediate products. Compared to the aqueous medium, the biphasic hydro-organic medium presents significant advantages such as increased effectiveness in the prevention of browning and an increased solubility of the resulting colored products. Thereby, the biphasic medium facilitates the separation of these products which were soluble only in the organic phase of this system.     

巴斯德芽孢杆菌培养基及培养条件的优化

通过单因素和正交实验对巴斯德芽孢杆菌(Bacillus pasteurii)培养基组分及培养条件进行研究。结果表明,最适培养基配方(g/L)为甘露醇40、大豆蛋白胨25、氯化铵3、氯化钠10,pH为8.0;最适培养条件为温度30℃,摇床转速200r/min,接种量4.0%(V/V),装瓶量75mL/250mL;在优化条件下,菌体培养24h达到生长高峰期,活菌数达9.52×109cfu·mL-1,分别是普通LB培养基和牛肉膏蛋白胨培养基的1.71、1.55倍。     

Survival of a probiotic, Lactobacillus casei strain Shirota, in the gastrointestinal tract: selective isolation from faeces and identification using monoclonal antibodies.

Lactobacillus casei strain Shirota (LCS) is a probiotic bacterium used in the production of fermented milk products and lactic acid bacteria preparations. To investigate the survival of LCS in the gastrointestinal tract, we have developed a selective medium and specific monoclonal antibodies to isolate and identify this strain. Selective LLV agar medium was prepared by modifying LBS medium, a selective medium for lactobacilli, through the replacement of glucose with lactitol as a carbon source and vancomycin as a selective antibiotic. Culture in LLV agar medium followed by ELISA using monoclonal antibodies specific for LCS was able to detect the organism in faeces. Using this method, we studied the faecal recovery of LCS in individuals who drank 125 ml of fermented milk which contained 10(10) live LCS for 3 days. The mean recovery was about 10(7) live bacteria per gram of faeces, indicating that LCS survived transit through the gastrointestinal tract after ingestion of the fermented milk.