基于多重连接探针扩增技术的食品中六重过敏原成分检测

基于多重连接探针扩增（multiplex ligation-dependent probe amplification,MLPA）技术建立了一种六重过敏原成分检测方法,可实现食品中大豆、芝麻、花生、杏仁、榛子和核桃6种成分的同时检测。选取多拷贝ITS基因为靶标基因,设计并合成6组特异性杂交探针。探针经杂交、连接和聚合酶链式反应得到扩增片段,经毛细管电泳分析扩增片段大小可明确区分6种过敏原成分。该体系经20余种相关植物、动物及微生物DNA验证显示其特异性良好,经模拟参考样品验证其检出限为5 mg/kg。30份不同种类市售食品MLPA检测结果表明,该方法性能满足实际样品的过敏原的多重检测。因此,本研究建立的基于MLPA技术的六重过敏原检测方法特异性强、灵敏度高,能够为食品过敏原评估、标识管理和风险控制提供技术支撑。     

多重连接探针扩增技术在食品安全检测中的应用研究进展

阐述了多重连接探针扩增(MLPA)技术在食品过敏原检测、食品掺假、食源性致病菌和转基因食品检测中的应用现状,并对该技术在食品安全检测领域的发展趋势和挑战进行展望。     

利用邻位连接技术检测花生过敏原成分

建立一种新型花生过敏原成分的快速筛选检测方法--邻位连接技术检测方法。针对花生过敏原选择适当的鼠源单克隆抗体,并合成针对花生过敏原的兔源多克隆抗体然后与磁颗粒偶联,而后将羊抗兔二抗与一条DNA分子耦联制成亲和探针1,将另一条寡核苷酸序列与羊抗鼠二抗耦联制成亲和探针2,上述成分能够与一连结DNA组合成邻位连接复合物,建立邻位连接检测花生过敏原的方法。使用3种花生过敏原标准品和10种确定不含花生过敏原的样本进行特异性试验;通过稀释花生过敏原标准品进行灵敏度验证。建立方法具有很好的特异性;检测标准品的灵敏度为0.01 ng/m L,比普通ELISA试剂盒灵敏度提高了1 000倍。建立的邻位连接检测花生过敏原的方法能够检测出使用目前常规方法不能检测到的花生过敏原,具有重要的实际意义。     

基于实时荧光PCR技术鉴别梅花鹿

目的建立基于TaqMan实时荧光PCR技术鉴别梅花鹿的分析方法。方法通过对梅花鹿线粒体D-loop基因序列比对分析,选取梅花鹿D-loop基因特异位点作为扩增靶序列,设计梅花鹿特异性的引物和TaqMan探针,并用已知样本对引物和TaqMan探针的物种特异性、灵敏性进行验证。结果该引物和探针对梅花鹿成分检测具有较强的特异性,与其他物种DNA无交叉扩增,该方法的检测灵敏度为0.01ng/μL。结论本方法具有较高的特异性和灵敏度,适用于对肉类以及其他梅花鹿产品的物种的鉴别。     

实时荧光聚合酶链式反应法检测食品中猪源性成分

针对猪线粒体细胞色素b基因序列设计特异的引物和探针,建立食品中猪源性成分实时荧光聚合酶链式反应检测方法,并经特异性和敏感性试验验证其可行性。结果表明：该体系可扩增猪肉DNA片段,长度为98bp,其他常见畜、禽肉成分均无法正常扩增。该体系灵敏度低至1pg,且阴性样品扩增后的Ct值限制在35循环以后。对于各模拟肉类样品中掺杂的猪源性成分,其检测限均达1%,经市售加工食品检测验证,表明所建立的猪引物探针体系具有特异性好、灵敏度高、快速、高效等优点,可用于对食品中猪源性成分的掺假鉴别检测。     

食品中马源性成分的实时荧光PCR检测

针对马线粒体DNA细胞色素b基因设计特异性引物和探针,建立食品中马源性成分实时荧光PCR检测方法,并经特异性和灵敏度试验验证其可行性。结果表明:该体系可扩增马DNA片段,长度为127 bp,其他常见畜、禽肉成分均无法正常扩增。该体系的检测灵敏度为1.25 pg马DNA和质量分数0.001%马肉粉。经市售食品的检测验证,表明所建立的马引物探针体系具有特异性好、灵敏度高、快速、高效等优点,可用于对食品中马源性成分的掺假鉴别检测。     

食品过敏原羽扇豆成分的环介导等温扩增 检测方法

目的 建立食品过敏原羽扇豆成分的环介导等温扩增(LAMP)检测方法。方法 根据羽扇豆的ITS基因设计羽扇豆的特异性引物,进行特异性、灵敏度、稳定性测试,建立LAMP检测方法。结果 本文建立的食品过敏原羽扇豆成分LAMP检测方法能有效对羽扇豆成分进行快速检测,具有较强的特异性和稳定性,灵敏度可达0.001%(w/w)羽扇豆粉。结论 该方法特异性强,灵敏度高,可以快速、准确检测食品中过敏原羽扇豆成分。     

环介导等温扩增法检测食品过敏原大豆成分

目的 建立食品过敏原大豆成分的环介导等温扩增(LAMP)分析方法。方法 根据大豆的内源管家基因Lectin基因设计6条过敏原大豆的特异性引物(两条内引物, 两条外引物和两条环引物), 建立LAMP检测方法。结果 环介导等温扩增法在63 ℃条件下, 40 min内可检出过敏原大豆成分, 该方法能够有效对大豆成分进行快速检测, 具有较强的特异性, 灵敏度可达0.01%(w/w)大豆粉。结论 该方法特异性强, 灵敏度高, 可以快速、准确检测食品中过敏原大豆成分。     

实时荧光PCR法检测食品中梅花鹿成分

采用实时荧光聚合酶链式反应技术检测食品中梅花鹿成分。通过对梅花鹿基因序列对比分析,选取种间差异大、种内差异小的线粒体细胞色素C氧化酶亚基Ⅰ基因序列作为靶序列,利用Primer Express、Oligo和DNAMAN等软件设计了梅花鹿特异性的引物和Taq Man探针,并用已知样本对引物和Taq Man探针的物种特异性、检测灵敏度进行验证和检测。实验结果表明,引物和探针对梅花鹿成分检测的特异性良好,与其他物种DNA无非目标扩增,对梅花鹿DNA的扩增效率为91.68%,该方法的检测灵敏度达0.42 pg/反应。     

两种PCR方法检测食品中花生过敏原Arah1成分

采用套式PCR和荧光实时定量PCR两种方法检测食品中花生主要过敏原Ara h1基因成分,从而推断食品中是否含有花生过敏原成分。根据GenBank提供的花生主要过敏原基因Ara h1 DNA序列(登录号为AF432231)的中一段序列分别设计2对内外特异性引物,扩增目的基因片段来建立套式PCR方法;再用上述内引物扩增目的片段,建立SYBRGreenⅠ荧光实时定量PCR方法,绘出拷贝数-CT标准曲线;并通过这2种PCR方法检测8种食品中含有花生主要过敏原Ara h1基因成分。套式PCR方法具有较高的特异性和灵敏度,SYBR GreenⅠ荧光实时定量PCR方法的标准曲线在3×102至3×108 copies范围内线性关系良好,R2值为0.993 5,检测低限设定为3×103 copies。2种方法检测8种食品样品,结果均与食物过敏原标注内容相符。本研究建立的2种方法具有快速、灵敏等优点,可用于食品中花生主要过敏原基因Ara h1成分的检测。     

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.     

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.