PCR鉴定牛羊肉串搀杂猪肉的方法建立

建立了一种鉴定牛羊肉中掺杂猪肉的PCR检测方法.确定了一对可在牛羊肉中特异并灵敏地检测出所掺杂猪肉成分的引物对,以猪细胞色素b基因组为模板.特异性扩增出130bp的目的片段,而无其他扩增片段影响.在牛羊肉中分别掺杂2%、4%、6%的猪肉,均可灵敏地检测出猪肉成分,无显著性差异;分别经120℃、10min,120℃、30min,115℃、30min,70%、16h处理猪肉,也可灵敏地扩增出特定目的条带,无显著性差异.     

环介导等温扩增技术在鸭源成分检测中的研究

为了建立肉产品中鸭源成分的现场快速检测技术,根据动物种间特异性的原则,筛选出一对品种特异的PCR引物,在此引物扩增片段的基础上,设计了环介导等温扩增(LAMP)引物序列,能特异检测鸭源成分。通过条件优化实验,发现在25μL的扩增体系中,内外引物浓度比为1∶4,温度为63.5℃,MgSO4添加量为5 mM/μL,dNTPs添加量为1.75 mM/μL,Bst DNA聚合酶添加量为0.4 U/μL,甜菜碱添加量为0.25μmol/μL,LAMP反应时间为30 min时,LAMP检测体系检测效果达到最优,鸭肉DNA的检测灵敏度可达到10 pg/μL。对牛羊肉中鸭源成分比例的检测灵敏度为0.000 1%。应用该方法对上海市闵行区市场中的牛羊肉产品进行抽样检测,结果从21份样品中成功检测出5份含鸭源成分的混合肉。本研究建立的LAMP检测方法灵敏、快捷,可以实现鸭源成分的现场速测,为肉制品市场的监管提供了一种新方法。     

肉制品中牛源性成分多重实时荧光PCR检测 方法的建立及初步应用

目的建立肉制品中牛源性成分的荧光PCR检测方法。方法根据牛特异性线粒体DNA片段,设计合成两对引物,以生、熟牛肉及超市牛肉加工品为材料,建立肉制品中牛源性成分的多重实时荧光PCR检测方法,并用该法与国标法同时对市售的25份肉制品同时进行检测,通过对其他种类的肉源DNA进行扩增验证方法的特异性;对含有不同比例牛肉成分的DNA样本进行检测确定检出限。结果该方法可成功检测出肉制品中的牛源性成分。在25份肉制品检测中,与国标法检测结果一致。该法的特异性为100%,灵敏度检测线为1%。结论本研究成功建立牛源性肉制品的检测方法,该方法快速简便,且具有较高的特异性和灵敏度,可用于市售肉制品中牛源性成分的鉴定。     

利用重组酶聚合酶扩增技术快速鉴定肉及肉制品中的猪源性成分

根据家猪线粒体细胞色素b的核苷酸序列设计和筛选实时荧光定量重组酶聚合酶扩增(Real time recombinase polymerase amplification,real-time RPA)反应所需的引物和探针,优化反应参数(Mg~(2+)和引物浓度),建立了一套利用real-time RPA技术进行肉及肉制品中猪源性成分的鉴定方法。应用此方法可以检测出肉及肉制品中低至0.2%的猪源性成分,且能够在恒温的条件下(40℃)15min中内完成反应,克服了传统聚合酶链式反应(Polymerase chain reaction,PCR)技术需要精密温度循环控制设备的局限性,是一种新型、简单、高效的检测方法,对实现快捷便携式的猪源性成分鉴定检测具有重要的意义。     

牛羊肉中猪源性成分检测能力验证研究

目的 了解我国食品检测实验室的牛羊肉中猪源性成分的检测能力。方法 国家认监委组织实施了牛羊肉中猪源性成分的检测能力验证工作, 22个省、市、自治区的38家实验室参加了本次能力验证。本研究介绍了本次能力验证的实施过程, 包括方案设计、样品制备、均匀性稳定性试验、结果统计等, 并对能力验证结果进行了分析。结果 实验室检测结果满意率为97.40%, 样品检测结果一致率为99.47%。结论 参加能力验证的绝大多数实验室可以准确检测牛羊肉中猪源性成分, 具备了分子生物学检测肉种鉴定的能力。     

毛绒制品的快速分子鉴定方法

为了快速准确地鉴定毛绒制品的成分,采用分子生物学手段建立了适用于羊毛、羊绒及羊驼绒的PCR扩增体系,同时进行方法特异性及灵敏度研究。结果表明利用设计的特异性引物可针对性扩增相应的Cytb的基因片段,利用片段长度不同可鉴别出不同的毛绒组分。利用该扩增体系扩增不同来源Cytb基因的灵敏度可达0.5%。采用建立的方法体系对混合毛绒制品进行了定性分析,结果显示当羊绒含量仅为0.5%时即可准确地鉴定出来。该方法简单易行且灵敏度高,可应用于毛绒制品日常检测。     

可视化核酸试纸条法快速检测肉及肉制品中鸭源成分

建立肉及肉制品中鸭源成分快速检测的可视化核酸试纸条法。设计鸭特异性引物,建立鸭成分检测可视化核酸试纸条方法,验证方法的特异性与灵敏度,并对市售肉及肉制品进行检测。该方法检测灵敏度0.1%,能够从鸭肉样品扩增出291 bp特异性DNA片段,而鸡、鹌鹑、猪、马、牛、羊、驴、鹿、骆驼、胡萝卜、白菜等动植物样品无扩增条带。建立的鸭源成分检测可视化核酸试纸条法特异性好,灵敏度高,简便,快速,是鸭源成分检测的有效方法。     

环介导等温扩增法快速检测牛羊肉中的掺杂肉

面对肉制品掺假突发事件频发的现状,对动物源性成分快检方法需求迫切。在等温扩增方法基础上,开展了肉制品掺假鉴定方法研究。以猪、鸡、鸭线粒体细胞色素b基因为目的序列,采用软件Primer Explorer Version5,通过序列比对设计并筛选环介导等温扩增(Loop-mediated isothermal amplification, LAMP)的特异性扩增引物。通过反应体系优化建立猪、鸡、鸭源性成分的环介导等温扩增技术分析方法,对常见9种动物源性成分进行特异性分析,检出限达到0.001 ng/μL,高浓度牛、羊DNA不影响方法检出限。通过分析模板脱氧核糖核酸(Deoxyribonucleic acid, DNA)浓度与反应循环数的关系,建立牛羊肉产品中,阈值为1%的猪、鸡、鸭掺杂成分的LAMP快速检测方法,分析时间36 min。采用该方法对深加工模拟掺杂肉样本分析结果与现行国家标准方法结果一致。研究可为肉制品原材料、市售生鲜肉及加工肉制品的肉成分快速筛查提供解决途径。     

微芯片电泳仪定量测定混合肉中各肉成分

目的基于微芯片电泳仪开发一种鉴定混合肉的定量方法。方法采用商品化试剂盒对不同比例混合的牛肉和猪肉进行处理,无需精制DNA,直接进行PCR过程。全自动的微芯片电泳仪,不仅可以测量DNA/RNA的片段长度,且采用了内标物和样品的同时出峰,通过两者峰面积的比值,可以测量出样品出峰片段的相应浓度。本文使用微芯片电泳仪测定不同比例混合的猪肉和牛肉目标PCR产物片段的长度和浓度,制作标准曲线。结果在猪肉和牛肉混合肉样品中检测到相应的目标PCR产物,并且两种肉的PCR目标产物浓度和样品的质量呈大致的线性关系。结论使用本方法可以实现混合肉中各成分的定量检测,为肉类掺假的鉴定提供了一种有力的分析手段。     

PCR方法快速鉴别食品中肉的种类

本文针对食品中肉成分种类鉴别开发了一种快速灵敏的PCR检测方法,可检测食品中是否存在猪肉、牛肉、羊肉以及鸡肉等成分。采用微波助提法提取样品中DNA,简化了前处理步骤,可在短时间内完成从多种不同类型肉与肉制品中提取肉成分DNA。为了评价方法的可靠性与灵敏度,猪肉以及掺入了不同比例浓度猪肉成分的食品样品采用本方法进行了核酸提取与PCR分析。检测结果表明,方法可检测出低至含有0.5%浓度的猪肉成分的混合样品。随机抽取50份不同类型的市面食品样品,检测出5份食品含有猪肉成分,7份食品中含有牛肉成分,5份食品中含有羊肉成分。该样品前处理方法、DNA提取方法以及PCR检测方法可广泛应用于食品中肉成分种类的检测鉴别。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status