四环素胶体金免疫检测技术的研究

为研制四环素(tetracycline,TC)胶体金免疫层析试纸条,对胶体金的制备及与四环素多克隆抗体的标记进行研究。采用柠檬酸钠还原法制备胶体金,向加热沸腾的100 mL0.01%氯金酸中加入1.8 mL1%柠檬酸钠,加热15 min后冷却定容;已制备好的胶体金溶液标记四环素抗体,将装有1 mL胶体金的离心管中加入一定量K_2CO_3调节p H值,加入一定量抗体蛋白后4℃条件下反应30 min,加入100μLNa Cl后4℃条件下保存备用,标记成功后优化条件。结果表明,胶体金颜色为紫红色、清亮透明、无沉淀及漂浮物,可见光光谱峰宽较小,证明胶体金大小分布均匀,制备成功;硝酸纤维素膜(NC膜)上有明显红色斑点,可见光光谱中最大吸收峰出现偏移,证明金标抗体标记成功;胶体金标记四环素抗体的最佳p H值为7.5,最佳标记蛋白量为稀释抗体6 000倍。胶体金的制备及与四环素多克隆抗体标记的成功,为装配四环素胶体金试纸条奠定了基础,为四环素在食品样品中快速检测方法的建立提供理论参考。     

纳米胶体金的制备及其抗体标记研究

研究通过光谱扫描,确定了柠檬酸钠还原法制备纳米胶体金的最佳条件:100mL0.01%四氯金酸溶液中添加1%柠檬酸钠2mL,反应10min,制备的胶体金粒径为15～20nm,并将其与抗牛β-酪蛋白IgG连接制得了胶体金标记抗体,通过考马斯亮蓝法测得蛋白标记率为74.5%,采用间接ELISA方法测得金标抗体的效价在1∶4000以上,抗体金标后活性良好,可以满足免疫检测的需要。     

胶体金侧向流免疫层析技术检测有机磷农药残留

目的在已制备出抗一类有机磷农药的组特异性单克隆抗体的基础上,制备胶体金,从而快速地对上述有机磷农药进行检测。方法通过鞣酸-柠檬酸三钠还原法制备出直径16.08±0.64 nm、质地均一的胶体金,并且以此标记单克隆抗体,组装胶体金免疫层析检测板。利用紫外光谱、荧光光谱、透射电镜、动态光散射等方法对胶体金及金标抗体进行鉴定。结果该检测板对标准毒死蜱的检测限为4μg/m L,检测时间为5 min。结论胶体金试纸条对毒死蜱具有较好的检测灵敏度,并且基质的干扰效应不明显。     

胶体金制备技术的改进与优化

采用柠檬酸三钠法、抗坏血酸还原法、柠檬酸三钠-鞣酸法3种方法制备胶体金,探索最优的制备方法。考察不同制备方法对胶体金外观颜色、颗粒大小以及均一性的影响。结果表明:采用0.22μm滤膜过滤的胶体金均一性较好,以100 m L 0.01%的四氯金酸溶液中2 m L 1%柠檬酸钠最佳的添加量的柠檬酸三钠法为制备胶体金最合适的方法。     

胶体金标免疫固相膜检测动物性食品中氟甲喹

氟甲喹(flumequine,FLU)是动物专用的抗生素,滥用或超标使用会造成动物性食品中的残留问题,对人类健康造成危害。以活泼酯法制备氟甲喹完全抗原,免疫新西兰大耳白兔获得抗血清,通过间接竞争酶联免疫法(enzyme linked immunosorbent assay,ELISA)测定抗血清的效价和亲和性,效价为1∶12 800,纯化后抗体的IC50达到0.055 ng/mL。采用柠檬酸三钠还原法制备胶体金,并用于标记FLU多克隆抗体制备免疫金。以硝酸纤维素膜为固相载体,包被上包被原和酶标二抗作为检测线和控制线,优化检测条件:封闭液为5%脱脂乳、酶标二抗稀释40倍、包被量1.0μg、免疫金稀释度1∶5(体积比)、金标抗体与待测溶液混合比例1∶5(体积比)。在最优条件下,制成FLU胶体金标记免疫固相膜,最低检出限达40μg/L。建立的胶体金标记固相膜免疫检测方法适于大量样品的快速定性筛查。     

检测三聚氰胺胶体金免疫层析试验的建立

采用混合酸酐法制备三聚氰胺-OVA偶联抗原,胶体金标记三聚氰胺单克隆抗体,建立了检测三聚氰胺的胶体金免疫层析试验.该试验具有较好的敏感性,最低可检测50μg/L的三聚氰胺.胶体金免疫层析试验对原料奶和奶粉样品中三聚氰胺的最低检测量分别为250μg/L和1000μg/L,可初步应用于基层实验室快速筛查检测.     

硝苯地平免疫胶体金探针的制备

目的优化硝苯地平药物的免疫胶体金探针的制备条件。方法采用柠檬酸三钠还原法制备胶体金溶液,采用紫外分光光度法在400~700 nm处测定胶体金溶液吸光度,判断胶体金颗粒大小。调整标记胶体金溶液p H、抗体蛋白量以及复溶液等因素,试制试纸条并进行加标验证实验,确定制备免疫胶体金探针的最优条件。结果实验制备胶体金颗粒大小在20~40 nm;最佳制备条件为:单抗标记p H为9.0,单抗标记量为5.0μL,复溶液为0.5 mol/L Tris(p H 9.0,含0.5%Tween20)。经加标实验验证,试纸条的检测灵敏度可以达到设计要求。结论硝苯地平免疫胶体金探针的制备条件优化,可为下一步制作高质量的免疫胶体金试纸条提供技术准备,可应用于对食品中非法添加硝苯地平的快速检测。     

T-2毒素快速定量检测试纸条的研究

为研制一种快速定量检测玉米中T-2毒素含量的胶体金试纸条,对T-2毒素单克隆抗体进行标记并对胶体金试纸条性能进行研究。用胶体金标记T-2毒素单克隆抗体,通过测定加入不同量碳酸钾后吸光度值的变化,确定标记的最佳pH值,通过与抗原进行正交试验确定最佳组合条件,应用胶体金定量读数仪通过检测线和对照线的对比,检测试纸条的性能。结果表明,单克隆抗体标记的最佳pH值为8.5,最佳标记浓度为20μg/mL,抗原的包被浓度为0.5mg/mL,羊抗鼠IgG的包被浓度为1.0mg/mL,试纸条检测T-2毒素标准品的检测限为5μg/kg。T-2毒素胶体金快速定量检测试纸条检测方法可得出具体数据,与常见真菌毒素无交叉反应,回收率在77%~117.6%之间,批内和批间重复性检测变异系数小于10%,玉米中T-2毒素的检测结果与高效液相法检测结果一致。T-2毒素胶体金快速定量检测试纸条可用于玉米中T-2毒素含量的快速定量检测。     

胶体金免疫层析法快速检测食品中金霉素残留

研究食品中金霉素残留的胶体金免疫层析法的快速检测方法。采用戊二醛交联法制备金霉素-BSA 免疫抗原,按照常规的免疫程序免疫新西兰大白兔制备抗金霉素多克隆抗体。纯化后的抗体用ELISA 法检测其特异性和效价。采用柠檬酸三钠还原法制备颗粒大小为15nm 的胶体金,并制备抗体- 胶体金复合物,以组装检测试纸。通过可见的颜色深浅,检测样品中金霉素的残留量。结果表明：试纸条法的金霉素检测限为0.7μg/mL,在四环素质量浓度大于1.0μg/mL 时,与金霉素存在交叉反应性,其结果与高效液相色谱法测定的结果一致。本方法检测时间仅需5min,适用于食品中金霉素残留的快速检测。     

李斯特菌免疫检测用胶体金的制备及抗体标记

单增李斯特菌是重要的食源性致病菌,可危害人体健康,造成经济损失。加强食品中单增李斯特菌的检测,是降低食品安全风险的有效手段。胶体金免疫层析技术以胶体金作为示踪物,结合抗原抗体反应应用于食品安全快速检测领域。通过柠檬酸三钠还原氯金酸的方法制备胶体金溶液。胶体金最佳制备条件为:25 m L 0.01%氯金酸水溶液中加入1 m L 1%柠檬酸三钠水溶液,反应时间5 min。利用李斯特菌菌体蛋白抗体标记胶体金来制备探针,最佳标记p H值为8.4,最佳标记蛋白抗体量为12μg/m L。制备的胶体金探针具有生物活性,可用于食品中单增李斯特菌快速检测方法的开发。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

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.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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