高灵敏度磁荧光免疫层析试纸模式构建及在呕吐毒素检测中的应用

构建基于磁荧光纳米材料的免疫层析试纸模式,弥补现在免疫层析技术的不足,为更灵敏的免疫学快速检测提供技术支撑。以呕吐毒素（deoxynivalenol,DON）为靶标,采用溶剂热法制备羧基修饰的超顺磁颗粒,碳二亚胺法将磁颗粒、绿色荧光蛋白及DON单克隆抗体进行偶联,一步法制备磁荧光抗体探针,以DON人工抗原（DON-BSA）为检测线建立磁荧光免疫层析试纸。同时用胶体金标记DON单克隆抗体,以DON-BSA为检测线建立胶体金免疫层析试纸;制备的磁荧光抗体探针具有很好的磁性、荧光特性及抗体反应性,基于该探针成功制备了DON磁荧光免疫层析试纸,该试纸回归方程为y=－0.562x＋0.921,R2=0.990,IC50为5.611 ng/mL,检出限为1.089 ng/mL;制备了DON胶体金免疫层析试纸,该试纸裸眼检测灵敏度为500 ng/mL;定量检测回归方程为y=－0.543x＋1.485,R2=0.991,IC50为65.16 ng/mL,检出限为11.94 ng/mL。DON磁荧光免疫层析试纸的灵敏度是胶体金免疫层析试纸的10.96 倍。本实验建立的磁荧光免疫层析试纸模式可以同时实现样品的富集及荧光信号检测,提高检测灵敏度,并成功用于DON的检测,为磁荧光纳米颗粒广泛应用于免疫层析领域提供参考。     

莱克多巴胺荧光微球免疫层析检测方法的建立

以荧光微球作为新型标记物,采用EDC法进行偶联,制备莱克多巴胺抗体荧光微球复合物,复合物粒度均一、性质稳定,并以之为探针建立莱克多巴胺荧光微球免疫层析检测方法,检测限为2.5ng/mL,且特异性强、检测范围宽。与胶体金免疫层析方法相比,荧光微球免疫层析方法的灵敏度更高,新型的荧光微球可以提高免疫层析方法的灵敏度。     

免疫快速同步检测玉米中五种真菌毒素胶体金试纸条的构建和应用

玉米作为重要的粮食和饲料来源，容易受到多种真菌毒素的污染，给居民健康和养殖业造成严重的危害。本文优化了适合五种真菌毒素（黄曲霉毒素B1、伏马毒素、T-2毒素、脱氧雪腐镰刀菌烯醇和玉米赤霉烯酮）同时提取的样品前处理方法，并构建了五检测线胶体金试纸条，检测结果可以通过肉眼定性，结合Image J软件可以进行定量分析，并应用于实际玉米样品检测。结果表明，最佳提取条件为90%乙腈/水，涡旋20 min，样品的添加回收率为71.9%-113.3%，相对标准偏差为0.9%-7.5%；测定基质添加样品建立标准曲线，通过肉眼判定得到五种真菌毒素的消线值分别为80.0、1000.0、100.0、400.0和200.0 μg/kg；结合Image J 软件提取多重检测试纸条的检测线灰度值，结果表明当AFB1、FB1、T-2、DON和ZEN的浓度为8.0、20.0、10.0、40.0、20.0 μg/kg时，各真菌毒素浓度对应的检测线显色值比空白对照显色值低。最后，通过检测11个实际玉米样品，结果表明部分玉米样品受到了不同程度的AFB1、DON和ZEN的污染。因此，本研究开发的免疫快速同步检测玉米中五种真菌毒素胶体金试纸条可以用于玉米中真菌毒素的现场快速筛查。     

基于磁性纳米探针的渔用麻醉剂三卡因的快速检测方法

该研究以超顺磁性纳米材料和三卡因的特异性单抗制备的磁性纳米探针作为标记物,以三卡因结构类似物3-氨基苯甲酸和牛血清蛋白的偶联复合物作为检测线(T线),以羊抗鼠IgG作为质控线(C线)构建层析试纸条,建立了一种渔用麻醉剂三卡因的快速检测方法.结果显示,该试纸条可通过肉眼观察,在5～10 min内检测鱼肉基质(2.5μg/...     

3种真菌毒素(ZEN、DON及T2)完全抗原的合成与鉴定

目的:合成玉米赤霉烯酮(ZEN)、脱氧雪腐镰刀菌烯醇(DON)和T2 3种真菌毒素的完全抗原。方法:将ZEN半抗原、DON及T2与阳离子化的载体蛋白(BSA和OVA)偶联,制备高特异性的完全抗原。用高性能基质辅助激光解吸电离-飞行时间质谱仪(MALDI-TOF)检测偶联物及载体蛋白的分子质量,用商品化的ZEN、DON和T2单克隆抗体对偶联物进行免疫滴定验证。结果:平均每个BSA偶联上的ZEN、DON和T2的分子个数分别为20.81,6.03,4.92个,平均每个OVA偶联上的ZEN、DON和T2分子个数分别为7.17,3.05,2.80个,偶联物与ZEN、DON及T2的抗体呈阳性反应。结论:合成的ZEN、DON及T2完全抗原为3种毒素抗体的制备及免疫学方法的建立奠定了基础。     

胶体金免疫层析法快速检测食用油中黄曲霉毒素残留

为建立用于快速检测粮油样品中黄曲霉毒素药物残留含量的胶体金免疫层析检测试剂,我们采用免疫竞争法,将抗黄曲霉毒素单克隆抗体-胶体金复合物包被在微孔中,并将人工合成的黄曲霉毒素抗原包被在硝酸纤维素膜(NC膜)表面作为检测线(T 线)。待测样品中的黄曲霉毒素残留物将与NC膜上的黄曲霉毒素抗原竞争结合胶体金标记的抗黄曲霉毒素单克隆抗体,并以颜色直观显示检测结果。检测食用油样品时,灵敏度可达到0.5μg/L,仅需20 min。实验证明该检测试剂具有较高的灵敏度及很好的特异性,操作便捷,稳定可靠,可作为黄曲霉毒素残留现场监控的有效快速筛检手段。     

胶体金免疫层析技术测定食品中黄原胶

目的:建立一种简便实用的胶体金免疫层析检测新方法,用于食品中黄原胶的快速筛查。方法:用黄原胶抗原标准品免疫新西兰大白兔,制备得到高效价的抗黄原胶多克隆抗体;采用柠檬酸三钠还原法制备胶体金,并将其与抗黄原胶多克隆抗体标记制得金标抗体;在硝酸纤维素膜检测线上,预包被黄原胶标准抗原,质控线上包被羊抗兔IgG,采用竞争法,制成黄原胶胶体金免疫层析检测试纸条,并对试纸条的特异性、敏感性和稳定性进行了试验。结果:该试纸条检测样品的敏感性为3g/kg。结论:研制出黄原胶胶体金免疫层析试纸条及其检测方法,该方法敏感性高、特异性强、操作简便,5min可出检测结果,可用于现场大量样品的快速检测。     

一种快速检测食用油中黄曲霉毒素B1的胶体金试剂板的研制

为建立用于快速检测粮油样品中黄曲霉毒素B1药物残留含量的胶体金免疫层析检测试剂,采用免疫竞争法,将抗黄曲霉毒素B1单克隆抗体-胶体金复合物包被在微孔中,并将人工合成的黄曲霉毒素B1抗原包被在硝酸纤维素膜(NC膜)表面作为检测线(T线).待测样品中的黄曲霉毒素B1残留物将与NC膜上的黄曲霉毒素B1抗原竞争结合胶体金标记的抗黄曲霉毒素B1单克隆抗体,并以颜色直观显示检测结果.检测食用油样品时,灵敏度可达到0.5 μg/L,仅需20 min.试验证明该检测试剂具有较高的灵敏度及很好的特异性,操作便捷,稳定可靠,可作为黄曲霉毒素B1残留现场监控的有效快速筛检手段.     

高灵敏黄曲霉毒素B1免疫层析定量检测法的建立

以胶体金为标记物,借助于胶体金读取仪,建立了高灵敏的定量检测黄曲霉毒素B_1的胶体金免疫层析方法。试纸条制备时,当标记溶液pH为6.0,检测线全抗原的使用浓度为1.5mg/mL,金标抗体浓度为4μg/mL、用量为1.2μL时,所建立方法的灵敏度为5.7ng/L。通过加速保存试验,结果显示该试纸条的保存期大于1年。该试纸条应用于实际谷物及酱油加标样本检测,证明该方法可满足食品快速检测的需要。     

量子点荧光微球免疫法定量检测小麦中黄曲霉毒素B1

摘 要: 目的 建立量子点荧光微球免疫法快速检测小麦中黄曲霉毒素B1的方法。方法 采用量子点荧光微球作为荧光标记物,与黄曲霉毒素B1的单克隆抗体偶联,构建量子点荧光微球探针。优化缓冲液pH、抗体最小标记量、荧光探针用量和包被抗原浓度等实验条件,建立检测卡上T线和C线信号峰值面积的比值与样本中黄曲霉毒素B1浓度的关系,构建定量标准曲线。针对小麦样品,将该检测方法与时间分辨荧光定量检测方法进行比较。结果 本研究建立的荧光定量免疫层析检测方法最佳反应条件为：pH 7.5磷酸钠缓冲液,抗体标记量为20 μg,荧光探针用量为4.0 μL,抗原质量浓度使用0.40 mg/mL。小麦中黄曲霉毒素B1的定量检测线性范围为0.05 μg/kg-25 μg/kg,其线性拟合方程为Y= -0.6058X + 12.523（r2=0.9994）,检出限为0.02 μg/kg,定量限为0.05 μg/kg。加标回收率在91.50%~115.00%之间,变异系数在1.88%~4.35%之间。结论 本研究建立的荧光定量免疫层析方法快速、准确、稳定性好、可靠性高,适用于小麦中黄曲霉毒素B1的现场快速检测。     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

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.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.