酶联免疫法快速检测奶粉中的叶酸

建立一种检测奶粉中叶酸质量分数的酶联免疫分析方法。奶粉样本经纯水溶解提取,再做1∶4稀释,通过酶联免疫吸附法(ELISA)测定奶粉中的叶酸。结果表明,当加标质量分数为20,40μg/kg和80μg/kg时,空白基质奶粉中叶酸的提取回收率为93.5%~118.0%;非空白基质样品中叶酸的加标回收率为88%~92%;方法检出限为4μg/kg;与高效液相色谱法结果的相对偏差小于10%。酶联免疫法能够快速、准确检测奶粉中的叶酸。     

高效液相色谱-串联质谱法测定牛奶和奶粉中9种青霉素类药物残留量

建立一种检测牛奶和奶粉中9种青霉素类药物残留量的高效液相色谱-串联质谱方法。样品经乙腈-水提取,经HLB固相萃取柱净化,用高效液相色谱串联质谱检测,外标法定量。本方法的检出限,牛奶中氨苄西林、奈夫西林为1μg/kg,阿莫西林、哌拉西林、青霉素G、青霉素V、氯唑西林为2μg/kg,苯唑西林、双氯西林为4μg/kg;奶粉中氨苄西林、奈夫西林为8μg/kg,阿莫西林、哌拉西林、青霉素G、青霉素V、氯唑西林为16μg/kg,苯唑西林、双氯西林为32μg/kg。9种青霉素在1.0～50ng/mL范围呈良好线性,线性相关系数大于0.9888。牛奶的平均回收率为77.58%～97.77%,测定结果的相对标准偏差为4.24%～16.59%(n=10);奶粉的平均回收率在85.95%～96.78%之间,相对标准偏差为2.71%～13.41%(n=10)。该方法具有简便、快速、准确度高、检出限低的优点,适用于牛奶和奶粉中青霉素类抗生素的测定。     

超高效液相色谱-串联质谱法测定奶粉中 己烯雌酚及玉米赤霉烯酮

目的建立超高效液相色谱-串联质谱法测定奶粉中己烯雌酚(diethylstilbestrol,DES)及玉米赤霉烯酮(zearalenone,ZEN)的分析方法。方法采用QuEChERS提取方法,奶粉加水浸润后用乙腈提取,加入氯化钠促使乙腈和水分层,取乙腈层经中性氧化铝小柱净化。以乙腈和水作为流动相,经ACQUITY UPLC?BEH C_(18)色谱柱分离后,利用超高效液相色谱-串联质谱法在电喷雾负离子模式下进行测定,内标法定量。结果DES和ZEN在5.0～100.0μg/L范围内线性关系良好(r~20.995),在5、10和50μg/kg 3个加标浓度水平下, DES和ZEN的回收率在91.5%～97.5%和92.5%～95.7%之间,相对标准偏差小于5%。结论该方法灵敏度高,定量准确,可同时测定奶粉中的己烯雌酚及玉米赤霉烯酮。     

液质联用法同时测定婴幼儿配方乳粉中氯酸盐和高氯酸盐残留

建立了婴幼儿配方乳粉中氯酸盐和高氯酸盐残留的高效液相色谱-串联四极杆质谱联用测定方法。样品经水超声溶解,乙腈除蛋白。以PC HILIC色谱柱分离,流动相为浓度50 mmol/L的乙酸铵水溶液和乙腈,流速0.25 mL/min。液相色谱-串联质谱仪测定,基质内标法定量。在该优化条件下,氯酸盐和高氯酸定量限分别为20μg/kg和2.0μg/kg,方法回收率为85.1%～94.7%,相对标准偏差(RSD)为2.38%～9.79%。经测定多种市售婴幼儿配方奶粉,表明该方法操作简单、测定结果准确,可用于婴幼儿配方奶粉中氯酸盐和高氯酸盐残留的同时快速测定。     

超高效液相色谱检测奶及奶制品中的M族黄曲霉毒素

目的建立一种免疫亲和柱净化-超高效液相色谱法同时测定奶及奶制品中M族黄曲霉毒素的方法。方法以乙腈为提取剂和蛋白沉淀剂,采用涡旋混合及超声提取,免疫亲和柱净化。结果经Welch Ultimate XB-C18色谱柱(100 mm×2.1 mm,1.8μm)分离,应用大体积流通池荧光检测,流动相为水和乙腈/甲醇(1:1)。线性范围在0.01~5.00 ng/mL之间,线性系数均大于0.999,黄曲霉毒素M1、M2的检出限为0.003μg/kg。免疫亲和柱对黄曲霉毒素M1、M2的回收率均在80%以上,液态奶中添加0.05、0.2、1.0μg/kg的回收率在85.6%~106.4%之间,奶粉中添加0.5、2.0、10.0μg/kg的回收率在81.5%~93.4%之间。结论该方法可以适用于奶粉、液态奶中M族黄曲霉毒素检测。     

应用HILIC技术检测乳制品中的尿素

基于亲水相互作用色谱(HILIC)技术,建立了可用于乳制品中尿素测定的液相色谱方法,其中固定相为Polar-Silica色谱柱,流动相为4 mmol/L磷酸二氢铵溶液(pH=6.8)-乙腈(20:80,体积比),检测波长为200 nm,流速为1 mL/min.在该体系下,尿素保留时间适中,可与其他几种含氮极性化合物如三聚氰胺、三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺等实现基线分离.应用该方法测定了奶粉和液态奶制品中尿素的质量分数,其中奶粉中尿素的质量分数为1 600～2 400 mg/kg,液态奶制品中尿素的质量分数为300～400 mg/kg.     

奶粉中VK1的超高效液相色谱定量和串联液质确证分析

建立婴幼儿奶粉中VK1的超高效液相色谱(UPLC)检测方法和液相色谱-串联质谱(LC-MS/MS)检测确证方法。经研究,对国标检测方法的前处理过程稍作改进,减少基质干扰,操作简便,提取率稳定。UPLC法检出限为40μg/kg(S/N=3),LC-MS/MS法检出限为3.5μg/kg(S/N=3);样本添加水平在500μg/kg～2 000μg/kg时,平均回收率为78.4%～88.1%,相对偏差(n=6)为3.7%～6.4%。该方法能够满足奶粉中VK1含量的准确测定。     

液相色谱法检测乌贼膏中牛磺酸含量

采用超纯水提取乌贼膏样品中的牛磺酸,与质量分数1%2,4-二硝基氟苯(DNFB)衍生后经高效液相色谱仪测定。结果表明:乌贼膏中牛磺酸平均回收率为97.44%,样品中的牛磺酸检出限为64.2mg/kg(信噪比S/N=3),定量限为213.9mg/kg(信噪比S/N=10)。     

液相色谱-串联质谱法同时测定婴幼儿配方奶粉中12种水溶性维生素

建立了同时测定婴幼儿配方奶粉中多种维生素、牛磺酸等12种水溶性维生素的液相色谱串联质谱测定法。采用MGⅢ-C18色谱柱,以质量分数为0.1%甲酸水溶液-甲醇为流动相(梯度洗脱),流速为0.25 m L/min,柱温25℃,进样量5μL。方法检出限0.0001~1 mg/kg,高、中、低不同质量分数加标回收率85.0%~95.5%,相对标准偏差为2.9%~9.1%。该法具有样品预处理简单,灵敏度高,分析时间短等优点,适用于婴幼儿配方奶粉中上述12种水溶性维生素的同时测定。     

气相色谱-质谱法测定牛奶和奶粉中啶酰菌胺残留

建立了一种牛奶和奶粉中啶酰菌胺残留的气相色谱-质谱测定方法.试样中的啶酰菌胺用乙腈提取,提取液经盐析、离心、浓缩和溶剂交换后,经凝胶渗透色谱净化,用气相色谱-质谱仪测定,外标法定量.方法的线性范围是0.010～0.50 mg/L.定量检出限(LOQ)牛奶为0.005 mg/kg,奶粉为0.040 mg/kg(均为质量分数),牛奶好奶粉中啶酰菌胺的添加质量分数为0.010,0.020,0.050 mg/kg时,回收率为88.6%～90.7%,相对标准偏差(RSD)为4.08%～5.95%.方法灵敏度高、选择性强、重现性好,适用于牛奶和奶粉中啶酰菌胺残留的定性确证和定量测定.     

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.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.