基于线粒体DNACOⅠ基因鉴别畜禽肉中鸡源性成分

为建立畜禽肉中鸡源性成分的快速检测方法,以线粒体DNA细胞色素C氧化酶亚基Ⅰ(COⅠ)基因序列为靶点,比较羊、牛、猪、兔、鸽、鹌鹑、鸡、鸭、鹅9种动物COⅠ基因的差异位点,设计筛选鸡特异性引物,进行常规聚合酶链式反应(polymerase chain reaction,PCR)和荧光定量PCR检测。结果表明:所设计的引物仅对鸡肉DNA模板有扩增条带和典型扩增曲线,且循环阈(cycle threshold,Ct)值为21.78,对其他动物DNA模板无扩增。方法特异性较强,灵敏度较高,达pg级,可以用于畜禽肉与肉制品中鸡源性成分的快速、有效、准确检测。     

利用荧光定量PCR技术鉴别畜禽肉中猪源性成分

以猪特异性基因序列为靶位点设计特异性引物,以常见畜禽肉包括猪肉、羊肉、兔肉、牛肉、鸽肉、鹌鹑肉、鸡肉、鸭肉、鹅肉等参考动物肌肉DNA为模板,进行荧光定量PCR扩增,建立猪源性成分荧光定量PCR检测方法;并将猪肉DNA模板浓度进行8个梯度稀释,检测其灵敏度。结果显示,该方法能够有效对猪源性成分进行快速检测,具有较强的特异性,灵敏度较高,可快速准确地鉴别畜禽肉中猪源性成分。     

荧光定量PCR方法检测畜肉食品中猪源性成分

目的 建立一种快速、特异、灵敏的猪源性成分检测方法。方法 本研究以猪线粒体12S rRNA基因序列为靶位点设计引物和探针, 进行荧光定量PCR扩增, 建立猪源性成分检测方法; 以常见畜禽肉包括羊肉、牛肉、鸡肉、鹅肉、鸭肉、兔肉、马肉、鹿肉等参考动物物种作特异性检测; 以50 mg/kg羊肉DNA作为稀释液对猪肉DNA进行梯度稀释, 做灵敏度检测。结果 该方法能够有效对猪源性成分进行快速检测, 具有较强的特异性, 灵敏度较高(可达0.1 μg/kg)并且羊肉成分的存在对猪肉灵敏度检测没有影响。结论 该方法特异性强, 灵敏度高, 可以快速、准确检测畜肉食品中含有的猪源性成分。     

实时定量PCR法对牛肉中鸡源性成份的量化检测

目的实现样品中牛源性成份和鸡源性成份的量化分析。方法通过在基因组单拷贝基因上设计引物,绘制模板DNA扩增标准曲线以及确定牛肉、鸡肉质量与DNA浓度的比值常数,利用实时荧光定量PCR技术对四种不同掺混比例的牛鸡瘦肉混合样本中牛源性成份和鸡源性成份所占的质量百分比含量进行分析。结果通过荧光实时定量PCR反应的Ct值、模板DNA扩增标准曲线和质量与DNA的比值常数可以计算出样品中所含牛源性成份和鸡源性成份的质量百分比含量,检测值与理论值之间的绝对误差可控制在5%以内,量化研究结果基本准确。结论对于组织成份单一的样品,可以通过在基因组单拷贝基因上设计特异性的引物,利用PCR技术实现在质量水平上对食品中动物源性成份的量化分析,该技术方法的建立可以为肉类掺假监管工作提供有力的技术支撑。     

一种基于多重实时荧光聚合酶链式反应熔解曲线分析的肉及肉制品掺假鉴别方法

为实现肉及肉制品掺假快速鉴别,分别以猪、牛线粒体DNA的COXⅠ,绵羊、山羊、狗、狐狸、貉线粒体DNA的16S rRNA及鸡、鸭线粒体DNA的12S rRNA基因为靶位点,设计扩增产物熔解温度(T_m值)具有显著性差异的特异性引物,建立一种用于快速鉴别肉或肉制品中猪、牛、绵羊、山羊、鸡、鸭、狗、狐、貉9种源性成分的5重实时荧光聚合酶链式反应熔解曲线分析方法,通过特异性、灵敏度及市售样品的检测,对该方法进行检验和评价。结果表明:方法具有良好的特异性及灵敏度,单物种DNA检出限为0.001~1 ng,多物种混合DNA检出限均为0.1 ng,通过市售样品检测表明该方法可用于实际样品(包括生鲜样品和熟制样品)掺假的快速鉴别。     

生鲜肉中牛源性和羊源性成分定量检测方法的建立

目的建立生鲜肉中牛源性和羊源性成分荧光PCR定量检测方法。方法以线粒体细胞色素b(Cytb)基因核苷酸序列为检测靶点,设计并优化引物,建立基于SYBR染料的荧光PCR定量检测方法,并对该方法进行特异性和灵敏度验证。结果在退火温度60℃的条件下,荧光PCR检测体系中各条引物特异性良好,目标成分检测信号Ct值均小于20,非特异性检测信号Ct值均大于35,该方法在模板浓度为0.016~10 ng/μL时线性关系良好;以Ct30作为阳性或阴性结果的判定限,目标源性成分荧光PCR定量检测的灵敏度可达1%。结论本方法可为生鲜肉制品种源鉴定和掺假检测提供理论依据。     

应用实时荧光PCR技术量化检测羊肉中猪源性和鸡源性成份

目的建立羊肉中猪源性成份和鸡源性成份的定量检测方法。方法以新鲜羊、猪和鸡瘦肉为样本提取DNA分子作为检测模板,针对基因组中单拷贝基因设计特异性的引物和探针,应用荧光实时定量PCR技术对模板DNA进行扩增。通过绘制扩增标准曲线和确定羊、猪和鸡的质量与DNA比值常数,对4种不同掺混比例的混合肉样进行定量分析。结果检测质量百分比的绝对误差可以控制在7%以内,量化结果基本准确。结论对于组织成份单一的样品,可以通过在基因组单拷贝基因上设计特异性的引物,利用PCR技术实现在质量水平上对食品中动物源性成份的量化分析,该技术方法的建立可以为肉类掺假的监管工作提供有力的技术支撑。     

基于DNA测序方法检测生鲜肉中5种动物源性成分

目的建立生鲜肉中猪、牛、羊、鸡、鸭源性成分的DNA测序鉴别方法,并对采集自北京各地区生鲜肉品进行检测验证。方法合成动物线粒体上12S rRNA、cytochrome b、cytochrome c oxidase基因引物,建立猪、牛、羊、鸡、鸭源性成分的DNA测序鉴别方法,并对50份猪、牛、羊、鸡、鸭肉品进行检测。结果使用线粒体上12S rRNA、cytochrome b、cytochrome c oxidase基因引物对猪、牛、羊、鸡、鸭肉品进行扩增,分别获得456、400和710 bp大小的DNA片段。只有12S rRNA基因引物均可对此5种动物源性成分扩增且效果良好。扩增产物进行序列测定。根据序列构建的系统进化树发现,此方法可有效区分样品中猪、牛、羊、鸡、鸭源性成分。结论此方法快速、简便,可准确检测50种生鲜肉样品中的动物源性成分,作为肉类鉴别的新方法。     

利用实时荧光定量PCR法检测食品中鹌鹑源性成分

为建立基于TaqMan实时荧光聚合酶链式反应(polymerase chain reaction,PCR)技术在食品中的鹌鹑源性成分的定量检测方法,根据现行检验检疫标准(SN/T 2727-2010)合成引物及探针。首先对13种不同动物鲜肉组织的DNA进行鹌鹑源性成分特异性检测,然后对鹌鹑源性DNA模板原液进行梯度稀释,检测方法灵敏度,最后在加工制品中检测方法的适用性。研究结果表明:建立的方法特异性强,除鹌鹑肉外,牛、羊、猪、马、驴、狗、兔子、鸡、鸭、鸽子、火鸡、鱼12种动物鲜肉组织均无特异性扩增;方法的灵敏度较高,鹌鹑组分DNA的检出限可达10 fg/mL,灵敏度可达0.001%;方法的适用性较广,可以用于加工制品中鹌鹑源性成分的检测。     

PCR法检测鱼及其制品中的鱼源性成分

目的:建立一种快速、特异、灵敏的鱼源性成分聚合酶链式反应(polymerase chain reaction,PCR)检测方法。方法:根据鱼线粒体基因组12S r RNA中的保守序列设计鱼源性特异性引物,进行PCR扩增,建立鱼源性成分检测方法;对24种鱼及鸡、牛、羊、猪、鸭、虾6种常见的易混于鱼制品的动物源性成分进行特异性检测;将草鱼肉混入其他动物肉中,混合均匀后提取DNA进行PCR扩增,确定肉样水平的检测灵敏度;将草鱼DNA混入其他动物DNA中,以混合后的DNA为模板进行PCR扩增,确定DNA水平的检测灵敏度。结果:该方法能特异性的对鱼源性成分进行快速检测,检测灵敏度达0.5%。结论:该方法能对食品中是否含有鱼源性成分进行初筛,到达快速检测的目的,对防止食品掺假、维护消费者利益、规范市场秩序有重要意义。     

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.     

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.     

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.     

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.