一起食物中毒事件中产独特肠毒素表型的金黄色葡萄球菌病原学分析

目的对一起疑似为金黄色葡萄球菌所导致的食物中毒事件进行葡萄球菌肠毒素检测,结合金黄色葡萄球菌病原学分析,为明确食物中毒诊断提供依据。方法根据流行病学调查,采用ELISA方法对可疑食物进行葡萄球菌肠毒素检测,同时对可疑食物和患者呕吐物进行金黄色葡萄球菌分离,运用Vitek2 Compact全自动细菌鉴定仪和血浆凝固酶试验鉴定为金黄色葡萄球菌,采用脉冲场凝胶电泳(PFGE)对病原菌进行同源性分析,以ELISA方法对检出的金黄色葡萄球菌菌株进行肠毒素检测,用PCR方法对肠毒素基因进行分型。结果食物和患者样品中分别分离出2和11株金黄色葡萄球菌,PCR方法及ELISA方法对肠毒素分型结果显示,其中12株同时存在SEA、SEB、SED、SEE 4种肠毒素及相关基因,PFGE聚类分析显示,其中12株产肠毒素金黄色葡萄球菌具有高度同源性。结论本起食物中毒事件为具有独特肠毒素表型的金黄色葡萄球菌导致,在金黄色葡萄球菌中毒实验室调查过程中,肠毒素检测结合病原菌溯源分析可以为相关公共卫生事件提供科学依据。     

利用简并引物检测金黄色葡萄球菌肠毒素A、B基因

通过设计简并引物建立一种PCR技术同步快速检测金黄色葡萄球菌肠毒素A和B基因的方法。根据金黄色葡萄球菌肠毒素A、B基因编码序列,设计一对特异性简并引物SEAB来扩增靶基因片段,长度分别为105bp和135bp,通过对金黄色葡萄球菌肠毒素A、B菌株和4株对照菌株进行PCR检测,评价该引物的特异性;对金黄色葡萄球菌肠毒素B的DNA系列10倍稀释,对其灵敏性进行PCR检测。结果显示,金黄色葡萄球菌肠毒素A和B菌株的DNA检测结果呈阳性,4株对照菌株的检测结果呈阴性,通过基因测序证实了PCR产物的特异性,SEB的DNA最低检测浓度为3.58ng,整个检测过程不超过20h。建立了一个特异、快速灵敏的在同一条件下,金黄色葡萄球菌肠毒素A、B基因的PCR检测方法。     

金黄色葡萄球菌肠毒素A、B、C在草莓中 表达的研究

目的研究金黄色葡萄球菌在草莓中生长情况及与3种肠毒素SEA、SEB、SEC产生的相关性。方法将实验菌株进行肠毒素分型确认后,分别制备10~4 CFU/g(高)、10~2CFU/g(低)两个浓度菌液,采用浸泡方式人工污染到草莓上,分别于8℃、25℃下贮存,贮存过程中参照GB 4789对草莓进行金黄色葡萄球菌计数和金黄色葡萄球菌肠毒素(A-C)检测。结果适宜条件下,无论初始污染程度高低,金黄色葡萄球菌都能在草莓上正常生长代谢并产生肠毒素,特别是SEA的产生较SEB和SEC迅速。其中,25℃贮存条件下,金黄色葡萄球菌累计到10~4 CFU/g以上就可从样品中检测到SEA,累计到10~5 CFU/g以上可以检测到SEC,累计到10~7CFU/g以上可以检测到SEB;8℃贮存条件下,48 h内未检测到肠毒素。结论以草莓作为金黄色葡萄球菌培养基质,获得了金黄色葡萄球菌生长及与3种常见肠毒素产生的相关性,对草莓微生物风险评估及相关标准制订具有参考意义。     

金黄色葡萄球菌肠毒素B的分离纯化

为了分离纯化金黄色葡萄球菌肠毒素B(SEB),在离心、浓缩后,将浓缩液依次经羧甲基阳离子交换纤维素CM-32和葡聚糖凝胶G-75两步柱层析,再经SDS-聚丙烯酰胺凝胶电泳分析,获得了电泳纯的金黄色葡萄球菌肠毒素B.实验证明,该简化的二步柱层析分离得到的SEB纯度高,方法简便易行,一般实验室均可采用.     

金黄色葡萄球菌肠毒素B的分离纯化

为了分离纯化金黄色葡萄球菌肠毒素B（SEB）,在离心、浓缩后,将浓缩液依次经羧甲基阳离子交换纤维素CM-32和葡聚糖凝胶G-75两步柱层析,再经SDS-聚丙烯酰胺凝胶电泳分析,获得了电泳纯的金黄色葡萄球菌肠毒素B。实验证明,该简化的二步柱层析分离得到的SEB纯度高,方法简便易行,一般实验室均可采用。      

辽宁省2018年食源性金黄色葡萄球菌脉冲场凝胶电泳分子分型及毒力基因的研究

目的 了解辽宁省食源性金黄色葡萄球菌的肠毒素分布情况及基因分型特征。方法 采用脉冲场凝胶电泳(pulsed field gel electrophoresis, PFGE)和肠毒素分型方法在不同角度和层次对2018年辽宁省内分离出的18株食源性金黄色葡萄球菌进行肠毒素检测与PFGE同源性分析。结果 PCR方法及酶联免疫吸附测定(enzyme-linked immunosorbent assay, ELISA)方法对肠毒素结果显示, 18株菌分别存在SEB、SEC、SED、SEH 4种肠毒素, PFGE聚类分析显示, 18株金黄色葡萄球菌相似系数在60.3%~100%之间。结论 金黄色葡萄球菌均可以用PFGE和PCR进行分型, 都具有较好地分型能力, 辨识度高, 对菌株有很好的溯源性。     

多重PCR检测金黄色葡萄球菌六型肠毒素基因的研究

目的:为了建立一种简单、快速检测金黄色葡萄球菌六型肠毒素基因的多重PCR方法。方法:根据相关文献和Genebank报道的编码金黄色葡萄球菌肠毒素A、B、C、D、E、H的基因序列,选择合成了6对特异性引物,建立多重PCR体系,并对反应条件进行了优化。结果:6对引物能同时特异地扩增出120、478、257、319、170、375bp的目的片段,表明6对引物具有良好的特异性。结论:成功地建立了一种同时检测金黄色葡萄球菌六型肠毒素基因的多重PCR方法,在金黄色葡萄球菌肠毒素快速筛查方面具有良好的应用前景。     

建立金黄色葡萄球菌肠毒素B悬浮芯片定量检测方法

目的建立金黄色葡萄球菌肠毒素B悬浮芯片定量检测方法。方法利用双抗体夹心法免疫学原理,以金黄色葡萄球菌肠毒素B的特异性抗体包覆微球为载体,利用悬浮芯片(Bio-Plex)系统建立检测模型;检测不同浓度金黄色葡萄球菌肠毒素B,测定方法的灵敏性;通过该方法对大肠杆菌、普通变型杆菌、蓖麻毒素和禽流感病毒HA、NH蛋白和金黄色葡萄球菌热休克毒素的检测,判断方法的特异性;将不同浓度金黄色葡萄球菌肠毒素B添加到奶粉中验证方法的实用性和稳定性。结果悬浮芯片方法对金黄色葡萄球菌肠毒素B的检测线性范围为0.2～1653.4ng/ml,最低检测值为203pg/ml,均优于酶联免疫吸附实验;除与2.3μg/ml金黄色葡萄球菌热休克毒素有交叉反应外,和其他几种细菌、毒素、蛋白均无交叉反应;对添加相同浓度金黄色葡萄球菌肠毒素B奶粉的检测的相对标准偏差在1.30%～16.93%。结论悬浮芯片定量检测方法对于模拟添加的金黄色葡萄球菌肠毒素B具有良好的检测效果。     

5 种葡萄球菌肠毒素基因MPCR-DHPLC检测方法的建立

设计合成5 种葡萄球菌肠毒素基因（SEA、SEB、SEC、SED、SEE）的特异性引物,对聚合酶链式反应（polymerase chain reaction,PCR）的反应体系进行优化后,建立5 种葡萄球菌肠毒素基因的多重PCR结合变性高效液相色谱（multiplex PCR-denaturing high performance liquid chromatography,MPCR-DHPLC）检测方法,并进行MPCR-DHPLC检测特异性及灵敏度的测定,5 重PCR-DHPLC检测灵敏度可达到100 CFU/mL。MPCR-DHPLC方法应用于食品中金黄色葡萄球菌肠毒素的检测,具有快速、准确、高通量等优点。     

食源性金黄色葡萄球菌肠毒素及其检测方法

金黄色葡萄球菌是一种重要的食源性致病菌,在自然界中广泛分布,其引起的食物中毒是世界性的公共卫生问题。金黄色葡萄球菌肠毒素是引起金黄色葡萄球菌食物中毒的主要致病因子。目前共发现22种金黄色葡萄球菌肠毒素或类肠毒素(SEA-SEE、SEG-SET、SElU、SElU_2和SElV),其中具有催吐活性的被定义为肠毒素,没有催吐活性或者尚待验证的被定义为类肠毒素(SEl)。传统肠毒素SEA~SEE被报道是引起金黄色葡萄球菌食物中毒的主要肠毒素类型,但是大多数新型肠毒素或类肠毒素与食物中毒的关系还没有被真正认识。本文对近几年关于金黄色葡萄球菌肠毒素与食物中毒的关系、肠毒素的表达调控以及肠毒素检测方法的研究进展进行了总结,以期更好地了解金黄色葡萄球菌新型肠毒素致病性,为今后金黄色葡萄球菌食物中毒的预防和控制提供依据。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press