间接竞争ELISA检测食品中的邻苯二甲酸二丁酯

以4-氨基邻苯二甲酸为原料,通过酯化反应合成半抗原4-氨基邻苯二甲酸二丁酯,将合成的半抗原通过重氮化反应与钥孔血蓝蛋白(KLH)进行偶联制备免疫抗原,与牛血清白蛋白(BSA)进行偶联制备包被抗原。通过免疫新西兰大白兔获得邻苯二甲酸二丁酯抗血清,利用纯化获得的抗体和包被抗原建立邻苯二甲酸二丁酯间接竞争酶联免疫检测方法(ELISA)。该方法的IC50为40.68μg/L,最低检测限IC_(15)为1.98μg/L,方法对邻苯二甲酸二丁酯具有较好的特异性。经对白酒、牛奶、食用油样品进行检测,添加回收率为84.57%～102.40%,用气相色谱—质谱法(GC-MS)进行验证,两种方法均呈现良好的线性相关性(R~2=0.990 8)。研究建立的方法可以被应用于食品中塑化剂邻苯二甲酸二丁酯的快速检测。     

氟乐灵抗体的制备及其酶联免疫分析方法的建立

该研究针对农(水)产品中氟乐灵农药残留的问题,建立了间接竞争酶联免疫分析方法,快速检测氟乐灵农药.利用3,5-二硝基-4-氯-三氟甲苯与仲胺侧链氨基反应合成半抗原2C,采用碳二亚胺法将半抗原2C与牛血清白蛋白/卵清蛋白偶联合成完全抗原.通过免疫新西兰大白兔获得多克隆抗体PcAb-2C,基于间接竞争酶联免疫分析方法原理对...     

米诺环素完全抗原的制备与表征

研究制备能有效用于米诺环素(MNC)残留检测的完全抗原。采用戊二醛合成法和重氮化合成法,将米诺环素与牛血清白蛋白(BSA)偶联,分别制备MNC 完全抗原MNC-BSA。经红外和紫外光谱扫描结果表明：两种物质已经偶联,两种完全抗原的平均偶联比分别为9.9 和5.9。采用戊二醛法合成的完全抗原免疫兔,检测抗血清效价为1:16000,表明合成的完全抗原可以作为免疫原用于制备抗体及检测时的包被原进行ELISA 检测。     

SM_2人工抗原合成研究

采用重氮化法合成磺胺二甲嘧啶(SM2)-人血清白蛋白(HAS)免疫抗原和SM2-卵清白蛋白(OVA)包被抗原。经紫外光谱扫描法确认SM2与载体蛋白偶联成功;经计算得SM2与HSA、OVA的结合比分别为9:1和15:1。     

α-乳白蛋白单克隆抗体的制备及斑点印迹定性检测方法的建立

以α-乳白蛋白为抗原免疫Balb/c小鼠,采用淋巴细胞杂交瘤技术制备抗α-乳白蛋白单克隆抗体;采用碳二亚胺法,并通过工艺优化,将单抗与量子点高效偶联;在此基础上,建立了基于斑点印迹技术定性检测乳制品中过敏原α-乳白蛋白的方法。结果表明:采用杂交瘤技术制备的单克隆抗体特异性好,与牛奶中其他蛋白无交叉反应;当量子点、1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC)、N-羟基丁二酰亚胺(NHS)、单抗摩尔比为1∶10∶6∶4时,量子点与单抗有较好的偶联效果;以量子点标记单抗建立的斑点印迹方法可直观、快速的定性分析乳制品中过敏原α-乳白蛋白。因此,该方法具有一定的实用价值。     

氯霉素全抗原的合成与鉴定

目的：为获得较高偶联率氯霉素全抗原,探索和优化碳二亚胺法(EDC)合成氯霉素(CAP)与牛血清白蛋白(BSA)全抗原合成条件。方法：采用单因素设计,优化影响合成的主要因素：蛋白浓度、CAP 与BSA 的摩尔比例、反应体系pH 值,通过紫外法和三硝基苯磺酸(TNBS)法测定合成后的偶联率。 结果：EDC 法合成氯霉素抗原较优条件为BSA 浓度15mg/ml、CAP:BSA=70:1、pH7.4,可得到偶联率为15 左右的氯霉素全抗原。结论：EDC法可用于制备较高偶联率的氯霉素全抗原,以用来进行抗体制备。     

甲基苯丙胺与蛋白偶联物的合成

研究合成甲基苯丙胺抗原.在甲基苯丙胺分子上引入偶联官能团,以牛血清白蛋白(BSA)为载体蛋白,用戊二醛法偶联合成了甲基苯丙胺抗原,并用红外光谱、紫外扫描、蛋白电泳以及胶体金免疫层析等方法进行检测.结果表明,每分子BSA连接甲基苯丙胺分子数为25;胶体金免疫层析检测结果显示合成抗原与抗体有特异性反应,具有活性.可在免疫检测中用作抗原的甲基苯丙胺与蛋白偶联物.     

三氯杀螨醇胶体金免疫快速检测试纸条研制及在茶叶中的应用

目的 建立一种基于胶体金免疫层析法的三氯杀螨醇快速检测试纸条的研制方法,并阐述其在新鲜茶叶中的应用。方法 以三氯杀螨醇为原料,用琥珀酸酐对其衍生化合成半抗原;用活化酯法将半抗原与白蛋白偶联得到人工抗原;用人工抗原免疫小鼠获得单克隆抗体。用上述原料制备出本研究试纸条。结果 所研制试纸条对茶叶中三氯杀螨醇检测限为0.2mg/kg,检测时间8min;可特异性地检测三氯杀螨醇的残留量,而对其他与三氯杀螨醇结构或功能相似的农药无交叉反应;准确性高;稳定性好;操作简便;检测成本低。结论 本研究提供的试纸条适宜基层实验室的大批量样本检测和田间现场快速检测,能够实现从源头上控制污染茶叶的流通上市。     

组胺胶体金免疫快速检测试纸条研制及其在水产品检测中的应用

目的 建立基于胶体金免疫层析法的组胺快速检测试纸条的研制方法,并探究其在水产品中的应用。方法 以组胺为原料,采用琥珀酸酐对其衍生化合成半抗原;活化酯法将半抗原与白蛋白偶联得到人工抗原; 用人工抗原免疫小鼠获得单克隆抗体。用上述原料制备出本研究试纸条,依据国家《食品快速检测方法评价技术规范》进行评价。结果 所研制试纸条对水产品中组胺检测限为高组胺鱼类400 mg/kg,一般海水鱼类及虾200 mg/kg, 检测时间8 min。可特异性地检测组胺的残留量,而对其他与组胺结构或功能相似的生物胺无交叉反应。结论 本研究提供的试纸条,操作简便,具有较高的灵敏度和特异性,可广泛应用于水产品中组胺的现场筛查和快速检测。     

氯霉素免疫检测方法的建立

采用碳二亚胺法(EDC)和混合酸酐法,分别与牛血清白蛋白(BSA)和卵清白蛋白(OVA)偶联制备氯霉素免疫原[CAP-HS-BSA]和包被原(CAP-HS-OVA)。经紫外和变性电泳(SDS-PAGE)鉴定,免疫原与包被原均制备成功,偶联比分别为1:16和1:17。利用免疫原免疫两只新西兰大耳白兔,制备多克隆抗体,建立间接竞争ELISA检测氯霉素残留的方法。建立的ic-ELISA检测氯霉素方法的半数抑制浓度(IC50)为7.275ng/ml,通过对氯霉素琥珀酸钠和链霉素、青霉素及庆大霉素的交叉反应率的测定,结果显示抗体对氯霉素琥珀酸钠有较高的交叉反应率而对链霉素、青霉素和庆大霉素的交叉反应率均小于0.1%。     

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.     

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.     

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.     

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.     

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.