水产品中氯霉素时间分辨荧光免疫层析定量检测方法

该研究旨在建立一种简单、快速、高灵敏的鱼、虾和蟹中氯霉素残留的荧光定量免疫层析检测方法,以满足水产品中氯霉素残留检测的需求。通过将氯霉素鼠单克隆抗体G375-5与羧基化铕微球进行偶联标记,氯霉素抗原和羊抗鼠二抗分别包被于硝酸纤维素膜(NC)上作为检测线(T)和控制线(C);根据T线信号值与C线信号值的比值(T/C)和样本中氯霉素浓度建立定量标准曲线;针对鱼、虾、蟹样品,对荧光免疫层析检测方法的灵敏度、准确度和精密度等进行评价,并将其在实际水产样品中与HPLC法进行结果对比。结果表明,该研究建立的时间分辨荧光免疫层析检测方法对水产品中氯霉素的定量限为0.1μg/kg,添加回收率为73.5%～114.2%,变异系数3.9%～11.5%,与国标仪器方法检测结果的一致性较高。因此,该研究所建立的时间分辨荧光免疫层析检测方法在水产品氯霉素的快速检测工作中具有较高的应用价值和应用前景。     

时间分辨荧光免疫层析法定量检测粮谷中重金属铅的研究

本研究制备了一种基于竞争抑制原理的粮谷物中铅快速检测的时间分辨荧光免疫层析定量检测卡。采用铕纳米微球作为荧光探针,标记抗Pb-EDTA的单克隆抗体,从而建立了免疫层析定量方法并对其进行方法学研究。结果表明:定量检测卡的灵敏度为0.61 ng/mL,标曲线性范围为1～16 ng/mL,检出限和定量限分别为8.70μg/kg和22.39μg/kg,对有证标准物质的检测回收率在93.2%～104.0%。该法精密度较好,变异系数在10%以内。结果显示,该法灵敏度高、操作简便、成本低廉,因此,非常适合基层单位,便于大量样本的快速初步筛查。     

量子点微球荧光免疫层析定量检测水产、畜禽肉组织中恩诺沙星

目的 建立一种快速定量检测水产、畜禽肉组织中恩诺沙星的新方法学。方法 以量子点荧光微球为新型标记探针,通过参数优化,制备获得量子点荧光微球免疫层析试纸条;进一步以T/C比值法建立定量检测恩诺沙星的新方法。结果 在最优条件下,该试纸条检测缓冲液中恩诺沙星半数抑制浓度为1.035 ng/mL,最低检测限为0.125 ng/mL;检测水产、畜禽肉组织中恩诺沙星的定量检测范围为8.75~560 μg/kg,半数抑制浓度为72.45 μg/kg,加标回收实验显示该方法定量检测组织样本中恩诺沙星的回收率在83.03~124%之间,变异系数小于15%,检测15个实际含有恩诺沙星的水产以及畜禽肉组织样本,其结果与LC/MS/MS方法检测结果高度一致;此外,加速保存实验结果显示该试纸条在室温下可保存一年。结论 本研究以量子点荧光微球为新型标记探针,构建了高灵敏定量检测恩诺沙星的新方法,实现了水产、畜禽肉组织中恩诺沙星的简单、快速、定量分析。     

荧光定量免疫层析法测定鸡肉和牛奶中的氯霉素

目的 建立一种荧光定量免疫层析法测定动物源性食品鸡肉与牛奶中氯霉素残留的分析方法。方法 将氯霉素鼠单克隆抗体与羧基化铕微球进行偶联标记。经过荧光微球活化、探针偶联等一系列条件优化确定最佳反应体系条件，根据纸条测试线(T线)信号值与质控线(C线)信号值的比值(T/C)和样本中氯霉素浓度建立定量标准曲线。针对鸡肉和牛奶样品，对荧光免疫层析检测方法的灵敏度、准确度和精密度等进行评价，并与液相色谱-串联质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS)标准仪器分析方法进行比较。结果 本研究建立的荧光免疫层析检测方法对鸡肉和牛奶中氯霉素残留的检出限(limit of detection, LOD)分别为0.041 μg/kg和0.040 μg/kg，定量限(limit of quantitation, LOQ)分别为0.079和0.100 μg/kg，添加回收率在76.26%~112.92%之间，变异系数均小于15%。结论 本研究建立的荧光定量免疫层析方法敏度高、稳定性好，且与使用仪器方法得到的检测结果一致性较高，适用于鸡肉和牛奶中氯霉素残留的现场快速检测。     

时间分辨荧光免疫层析法定量检测稻谷中的镉

本研究制备了一种用于稻谷中镉检测的时间分辨荧光免疫层析定量检测卡。采用铕纳米微球作为荧光探针,标记抗Cd-EDTA的单克隆抗体,基于竞争抑制原理建立免疫层析定量方法并对其进行方法学研究。结果表明：定量检测卡的灵敏度为0.088 ng/mL,标准曲线线性范围为0.1ng/mL～5.0 ng/mL,检出限和定量限分别为0.026 mg/kg和0.064 mg/kg,对有证标准物质的正确度在81.0%~91.7%之间,对实际样本的检测与ICP-MS检测结果一致性较高。该法重复性较好,变异系数在10%以内。结果显示,该法灵敏度高、操作简便、成本低廉,因此,非常适合基层单位大量样本的快速初步筛查。     

水产品孔雀石绿和隐性孔雀石绿快速定量检测研究

采用胶体金免疫层析方法建立了水产品中孔雀石绿和隐性孔雀石绿的定量检测,并对其样品前处理方法进行了研究。结果表明,孔雀石绿的线性范围为0.25μg/L~8μg/L,线性系数0.996 1;优化后孔雀石绿提取液的pH为4.5,对甲苯磺酸浓度为0.06 mol/L,净化剂为2 g中性氧化铝,脱水剂为2 g氯化钙,氧化剂为100μL 0.1%四氯苯醌;孔雀石绿加标回收率为80.1%~89.6%,隐性孔雀石绿加标回收率为66.9%~72.9%,相对标准偏差1.07%~8.14%。     

荧光定量法快速检测鲜奶中四环素类总量残留

以荧光纳米微球标记抗体,建立免疫层析检测方法,配合荧光定量仪,可高灵敏度地检测样本中4种四环素类药物的残留含量,实现鲜奶中所含四环素类药物的总量检测。结果表明,本方法对四环素的检测下限达10μg/L,对金霉素、土霉素、多西环素回收率均达70%以上,除了与链霉素有0.32%的交叉反应率外,与其他药物没有交叉反应,整个检测过程只需15 min左右。通过建立的荧光定量免疫层析法,实现了四环素总量的快速定量检测。     

胶体金免疫层析法检测水产品中孔雀石绿总量残留

目的建立胶体金免疫层析法快速检测水产品中孔雀石绿总量的残留。方法用柠檬酸三钠还原法制备胶体金并标记孔雀石绿单克隆抗体。基于竞争抑制反应原理,在优化条件下建立胶体金免疫层析法。结果水产品中孔雀石绿总量的检测限为2μg/mL,与结构类似物结晶紫的交叉反应不明显。实际样本检测结果与液相色谱-串联质谱法检测结果的差异较小。结论该方法快速、有效,可满足现场检测水产品中隐性孔雀石绿及孔雀石绿的残留。     

荧光微球免疫层析方法定量检测水产品中4 种硝基呋喃代谢物

采用荧光微球标记抗体作为信号探针,建立荧光微球免疫层析检测方法（fluorescent microsphere immunochromatographic assays,FMICA）,并应用于水产品中4 种硝基呋喃类兽药代谢物残留量的快速定量检测。结果表明：呋喃妥因、呋喃它酮、呋喃唑酮、呋喃西林代谢物FMICA试纸条的检出限分别为0.004（以1-氨基-乙内酰脲衍生物计算）、0.01（以5-吗啉-3-氨基-2-恶唑烷酮衍生物计算）、0.008（以3-氨基-2-恶唑烷酮衍生物计算）、0.009（以氨基脲衍生物计算）μg/L;检测线性范围分别为0.005～5、0.01～10、0.01～10、0.01～10 μg/L;最佳检测时间为10 min,方法特异性良好。水产样品经衍生化处理后,经检测硝基呋喃代谢物的加标回收率在75.88%～104.81%之间,变异系数均小于15%。FMICA方法操作简单、快速、成本低,适用于水产品中硝基呋喃类兽药代谢物快速定量检测。     

呕吐毒素时间分辨荧光免疫层析法的建立与评价

构建并评价了呕吐毒素(Deoxynivalenol,DON)时间分辨荧光免疫层析法(TRFIA)。以Eu3+螯合物的纳米微球为荧光探针标记抗DON单抗,采用竞争抑制建立免疫层析定量方法,优化了微球与抗体标记量,检测的环境温度、反应时间、加样体积及缓冲体系;研究了方法的灵敏度、精密度及准确度。结果表明,每100 μL荧光微球结合纯单抗50 μg,最佳划膜浓度为1.0 mg/mL,最佳测定条件为室温(25±2)℃,10 min,加样体积100 μL,PBS (0.01 mol/L,pH7.2)的缓冲体系,方法的灵敏度为0.25 ng/mL,线性范围为0.5~25.0 ng/mL,玉米、小麦阴性样本(加标浓度200、500、1000、2000 μg/kg)平均加标回收率为91.4%~109.3%,6种典型样本经TRFIA与免疫亲和净化-高效液相色谱法(IAC-HPLC)同时测定DON含量,相关系数r达0.9754。TRFIA具有灵敏度高、速度快、定量准等技术特点,适用于谷物及制品中DON的快速定量。     

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.     

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.     

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.     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.