免疫磁珠-PCR试纸条快速检测食品中牛源成分方法的建立

建立食品中牛成分快速检测的免疫磁珠-PCR试纸条方法。免疫磁珠提取食品中核酸,设计牛特异性引物,建立牛成分快速检测的PCR-试纸条方法。验证方法的特异性、灵敏度和稳定性。该方法检测灵敏度0.01%,能够从食品中扩增出561 bp特异性DNA片段。建立的食品中牛成分检测的免疫磁珠-PCR试纸条法特异性好,灵敏度高,简便,快速,是食品中牛成分检测的有效方法。     

PCR-核酸试纸条法检测食品中假结核耶尔森菌

目的 建立一种基于PCR-核酸试纸条技术快速检测食品中假结核耶尔森菌的方法。方法 将10株假结核耶尔森菌株和9株其他耶尔森氏菌及18株来源菌株作为实验菌株进行特异性实验; 通过纯菌液计数、干扰菌实验检测进行灵敏度验证。结果 DNA检测可达到10?3 μg/mL, 25 g样品加菌实验灵敏度可达 100 CFU/25 g, 添加10倍干扰菌不会降低检测灵敏度。利用建立方法对市场购买的食品进行筛查并与国标方法进行比较, 建立方法的灵敏度优于国标方法。结论 该方法检测结果准确, 灵敏度高, 适用于检测食品中假结核耶尔森菌。     

核酸试纸条法检测食品中小肠结肠炎耶尔森菌

建立一种基于聚合酶链反应(polymerase chain reaction,PCR)试纸条技术的快速检测小肠结肠炎耶尔森菌的检测方法。对26株小肠结肠炎耶尔森氏菌标准菌株及26株其他菌属标准菌株进行特异性试验,利用纯菌稀释及样品添加进行灵敏度试验。利用建立方法对市场购买的食品进行筛查并与国标方法进行比较。建立的方法 DNA检测灵敏度达到10~(-3)μg/mL,样品加菌试验检测灵敏度可达100 CFU/25 g。     

环介导等温扩增结合免疫层析试纸条快速检测羊肉及其制品中的鸭源成分

为实现肉及肉制品中掺假成分的快速检测,本文将环介导等温扩增技术(loop mediated isothermal amplification,LAMP)与免疫层析试纸条(immunochromatographic test strip,ICTS)相结合,建立了一套可在羊肉及其制品中特异并灵敏地检测出鸭源性成分的方法。根据鸭特异性细胞色素b(cytb)基因的6个特异性区域设计LAMP引物,其中两条内引物FIP和BIP分别使用生物素(biotin)和地高辛(digoxin)标记。使用LAMP扩增技术于65℃下扩增30 min产生生物素和地高辛标记的双链DNA产物,将扩增产生的双链DNA产物(10 μL)与90 μL上样缓冲液(PBS pH=7.4)混合均匀后使用免疫层析试纸条进行可视化检测。本研究所建立的LAMP-ICTS方法能够在40 min内特异性地检测出羊肉及其制品中的鸭源成分,且与其他肉类不存在交叉反应,检出限可达到0.01%(w/w)。市售实际样品检测结果显示,所采集的羊肉片、羊肉串样品中均有鸭源性成分,且此结果与行业标准方法(PCR-电泳)的检测结果一致。LAMP-ICTS方法具有灵敏度高、特异性好、检测速度快、对仪器的依赖低等优点,适用于基层监管部门对羊肉及其制品真伪进行快速检测。     

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。     

免疫层析试纸条信号放大技术研究进展

免疫层析试纸条（Immunochromatographic Test Strip, ICTS）是建立在毛细管层析技术和抗原-抗体特异性反应基础上的一种检测技术,具有成本低、操作简单、不需要专业人员、分析时间短、特异性强和结果肉眼可见等特点,目前被广泛应用于食品安全快速检测中。基于传统球状金纳米材料的ICTS是目前最为常见的方法。但是传统方法仅能实现定性或半定量检测,其低检测灵敏度无法满足现在的检测需求。因此,利用信号放大技术来提高ICTS的灵敏度越来越受到人们的关注。本文总结了ICTS的信号放大策略并提出了未来的发展方向,以期为食品安全快速检测技术的发展提供技术参考。     

免疫层析试纸条在食品安全检测中的应用

随着现代食品安全问题的日益凸显,研发快速、准确、低成本的食品安全检测方法具有重要意义。免疫层析试纸条作为一种常用的检测工具,已被广泛应用于食品安全领域。本研究旨在探究免疫层析试纸条在食品安全检测中的应用潜力。通过对相关文献进行综述,可知免疫层析试纸条具有高度的选择性和敏感性,能够迅速检测出食品中的有害物质和致病菌。此外,免疫层析试纸条还具有操作简便、不需要复杂仪器设备、检测周期短等优点,适用于在实验室和现场进行食品安全快速检测。     

基于胶体金免疫层析技术的赤霉素快筛试纸条的研制

研制快速检测豆芽中赤霉素的快筛试纸条。采用免疫层析技术,以胶体金为标记物制备赤霉素单克隆抗体-胶体金偶联物,以竞争抑制模式制备赤霉素胶体金免疫层析试纸条。该试纸条对豆芽中赤霉素的检测限为100 μg/kg,灵敏度为98%,特异性为97%,假阴性率为2%,假阳性率为3%。该方法操作简便,具有较高的灵敏度和特异性,可广泛应用于豆芽中赤霉素残留的现场筛查和检测。     

免疫层析试纸条技术在食品安全领域的研究进展

免疫层析试纸条技术（Immunochromatographic Test Strip,ICTS）结合了色谱分析的分离能力和免疫分析的特异性,具有操作简单,检测快速以及价格低廉的特点,已成为食品安全快速检测领域研究的热点。传统的ICTS是以胶体金作为信号标记材料,但是胶体金试纸条检测灵敏度较低,只适用于定性和半定量检测。为了提升试纸条的检测性能,研究者做了大量的努力。本论文介绍了传统的胶体金试纸条的检测基本原理,并对近年来开发的试纸条检测新技术进行综述,同时也提出该项技术目前所存在的局限性并提出了未来的发展方向,以期为试纸条的进一步开发利用提供一定的文献支持。     

呋喃唑酮代谢物单克隆抗体和胶体金免疫层析试纸条的研制

本研究旨在建立一种快速检测呋喃唑酮代谢物残留的方法。试验用呋喃唑酮代谢物的衍生物（CPAOZ）与牛血清白蛋白（BSA）的偶联物免疫小鼠,利用单克隆抗体技术制备杂交瘤细胞,用间接ELISA和间接竞争ELISA法对阳性克隆进行筛选。单克隆细胞株诱生腹水后,经纯化即为单克隆抗体,用于胶体金标记,制备呋喃唑酮代谢物胶体金免疫层析试纸条。融合后得到2株稳定分泌抗体的杂交瘤细胞株,其中4G3纯化后的抗体效价达到1:100万,对CPAOZ的50%抑制质量浓度（IC50）为1.7 μg/L,亲和常数Ka=1.6×109 L/mol。该抗体制备的胶体金试纸条的检测限为4 μg/L,与其他3种硝基呋喃代谢物的衍生物CPAHD、CPSEM和CPAMOZ均不存在交叉反应,对样品的检测与高效液相色谱结果一致。本研究制备了抗呋喃唑酮代谢物特异性单克隆抗体,并研制了以单抗为基础的胶体金免疫层析试纸条,能够实现呋喃唑酮代谢物残留的快速、灵敏的检测。     

Identification of tuna species by a real-time polymerase chain reaction technique

Tuna are highly priced fishes that are often used in processed products. For effective fishery management and protection of consumers’ rights, it is important to develop a molecular method to identify the species of the tuna products. In this study we have developed a molecular method based on real-time polymerase chain reaction (real-time PCR) technology for the rapid identification of four tuna species. Four species-specific TaqMan probes were designed to identify bigeye tuna (Thunnus obesus), Pacific bluefin tuna (Thunnus orientalis), southern bluefin tuna (Thunnus maccoyii), and yellowfin tuna (Thunnus albacares). A SYBR green system was also designed to enhance the authentication of T. obesus. Both systems can distinguish target species from others in an efficient and high-throughput manner and can be applied to species identification of tuna products.     

纳米酶侧流免疫层析法快速检测食品中肠炎沙门氏菌

目的 基于氧化铈修饰的金纳米棒(CeO2 modified Au nanorod, AuNR@CeO2)纳米酶构建纳米酶侧流免疫层析法(lateral flow immunoassay, LFIA), 并用以检测食品中肠炎沙门氏菌。方法 采用模板法制备AuNR@CeO2纳米酶, 对纳米酶的酶促活性进行考察。将AuNR@CeO2标记抗体作为信号探针进一步构建试纸条, 优化其关键参数, 并利用AuNR@CeO2纳米酶的酶促活性, 催化放大试纸条的比色信号, 最后将其用于奶粉中肠炎沙门氏菌的检测。结果 成功制备了AuNR@CeO2纳米酶, 在最优条件 下(即：2% BSA+0.05% Tween-20的样品垫缓冲体系、0.8 mg/mL的T线抗体质量浓度和4 μL的探针使用量), 该试纸条可以实现目标菌的特异性检测, 检出测限 低至103 CFU/mL, 信号放大后灵敏度提高了10倍, 在人工污染奶粉样品中也表现出良好的检测效果 检出限低至103 CFU/mL。结论 本研究所制备的试纸条无需复杂仪器和专业人员即可实现目标物的检测, 且具有易操作、便携、快速的特点, 通过更换抗体类型便可用于各类食品有害物质的检测。     

Gold nanoparticle-based lateral flow assay for detection of staphylococcal enterotoxin B

The lateral flow assay (LFA), a rapid, sensitive, and reproducible technique, was successfully applied to detect staphylococcal enterotoxin B (SEB). The assay was based on a double-antibody sandwich format on a porous nitrocellulose membrane. When SEB-containing samples were applied to the LFA-device, the toxin initially reacted with polyclonal antibody (Pab)-coated colloidal gold particles and then reacted with the fixed Pab on the membrane. These reactions resulted in a red line at the detection zone, with intensity proportional to the SEB concentration (under 100 ng/ml). With this method, 1 ng/ml of SEB can be detected in less than 5 min and was highly reproducible. Signal can be amplified to 10 pg/ml by silver enhancement. This assay also showed no cross-reaction with other SEs, such as SEA, SEC, SED and SEE. The assay was significantly faster than the ELISA or real-time PCR assay and should facilitate early and rapid SEB detection in clinical and food samples.     

荧光微球免疫层析法定量检测牛乳中酪蛋白

目的研究用荧光微球免疫层析法定量检测牛乳中的酪蛋白。方法本文以酪蛋白为抗原,免疫新西兰大白兔制备抗酪蛋白的多克隆抗体,将纯化后的多克隆抗体通过EDC介导法与荧光微球进行偶联,将滤纸、样品垫、结合垫、NC膜和吸水纸组装成试纸条,用此荧光微球免疫层析法定量检测牛乳中的酪蛋白。结果试纸条在25 min内就能判定结果,最低检测限为100 ng/mL,该方法与BSA、OVA均无交叉反应,具有很好的特异性。检测酪蛋白浓度为100.0、500.0、1000.0 ng/mL的样品,试纸条的批内回收率分别为(89.03±5.2)%、(93.47±6.9)%和(91.2±7.8)%,批间回收率分别为(87.69±6.2)%、(92.73±8.3)%、(89.82±8.5)%。结论初步建立了一种快速、方便、高灵敏度的荧光微球免疫层析方法用以检测牛乳制品中的过敏原——酪蛋白。     

Optimization and evaluation of a modified enrichment procedure combined with immunomagnetic separation for detection of E. coli O157:H7 from artificially contaminated alfalfa sprouts

Escherichia coli O157:H7 has been linked to foodborne disease outbreaks with alfalfa sprouts. Detection of the organism in sprouts by standard cultural methods can be difficult due to the high background microflora. The objective of this study was to develop and optimize an enrichment protocol with and without post-enrichment immunomagnetic separation (IMS) for the rapid detection by real-time PCR (RTiPCR) and cultural recovery of E. coli O157:H7 from artificially contaminated alfalfa sprouts. Initially we found that the FDA BAM procedure, enriching samples in modified buffered peptone water with pyruvate and at 37 °C for 5 h, followed by the addition of acriflavin, cefsulodin and vancomycin (mBPWp + ACV) and static incubation at 42 °C gave poor results for both PCR detection and isolation for alfalfa sprouts artificially contaminated at 0.2 cfu/g. The addition of post-enrichment IMS improved detection but not isolation. This procedure was modified and optimized by changing to mBPWp with cefsulodin and vancomycin at 42 °C and shaking for 24 h with and without IMS prior to PCR detection and cultural isolation. Using the resulting protocol we were able to detect E. coli O157:H7 in 100% of samples of alfalfa sprouts contaminated at 0.2 cfu/g. This was validated for five strains of E. coli O157:H7. Isolation was 84% without added post-enrichment IMS and 100% with IMS. The optimized procedure was effective for detection and isolation of E. coli O157:H7 from this difficult food matrix.     

A novel extraction method for peanut allergenic proteins in chocolate and their detection by a liposome-based lateral flow assay

In this study, conditions for extracting the major peanut allergen (Ara h1) from chocolate were optimized, and the extracted samples were analyzed by a lateral flow assay (LFA) using liposomal nanovesicles. The optimal conditions using peanut-spiked chocolate were found to be extraction with a mixture of phosphate buffered saline and hexane for 30 min at 35 °C. After centrifugation, the buffer portion was treated with insoluble poly(vinylpolypyrrolidone) to remove phenolic compounds, and then analyzed by the LFA. The entire analysis, including sample preparation and LFA, could be easily completed within 2 h, and the detection limit was 158 g of peanuts/g of chocolate.     

Rapid detection of Listeria monocytogenes using fluorescence immunochromatographic assay combined with immunomagnetic separation technique

To ensure the safety and quality of food ingredients, especially meat and dairy products, a high‐throughput, rapid and sensitive method to detect Listeria monocytogenes (LM) is always on a high demand. In this work, a specific induction method to enrich and detect LM based on fluorescence immunochromatographic assay (FICA) combined with immunomagnetic separation (IMS) techniques has been developed. The immunomagnetic‐beads (IM) beads were obtained through functionalised magnetic microspheres and the conjugated reaction between the carboxyl on beads surface and amino groups of antibody. The prepared IM‐beads could be used for rapidly enriching pathogenic bacteria with fewer steps, resulting in a high specificity for four pathogenic serotypes and about a 40‐fold improvement of detection limit compared with FICA only. In addition, this method was successfully applied in LM detection in sausage, pork and milk samples with a potential for further application in rapid on‐site detection of pathogenic bacteria.     

Rapid detection of Salmonella in milk by combined immunomagnetic separation-polymerase chain reaction assay

During the past few years, milk has presented a risk of Salmonella contamination; it has been implicated as the cause in several outbreaks of salmonellosis. Because conventional detection methods require 5 to 7 d for completion and involve several subcultivation stages followed by biochemical and serological tests, rapid and sensitive methods have been sought, mainly at the DNA level. Therefore, a study including milk samples was conducted to evaluate the performance of a combination of 2 techniques—immunomagnetic separation and polymerase chain reaction (PCR)—for the detection of Salmonella. The 16-, 14-, 12-, 10-, and 8-h nonselective pre-enrichment steps before immunomagnetic separation and the high-pure DNA preparation method before PCR were used in a combined assay. Milk samples, which were found to be Salmonella-negative by a reference method, were first inoculated with Salmonella Enteritidis. Next, the shortest pre-enrichment time that is required for detection of 1 or 10 cfu of Salmonella/mL by combined immunomagnetic separation-PCR assay was found by using 16-, 14-, 12-, 10-, and 8-h incubation periods. The detection limit using a 16-, 14-, or 12-h nonselective pre-enrichment was 1 to 10 cfu/mL. However, the sensitivity decreased to 10¹ and 10² cfu/mL, respectively, when 10- and 8-h pre-enrichments were used. This assay, in conjunction with a 12-h pre-enrichment, proved to be rapid (overall 16 h) and sensitive (1-10 cfu/mL) for the detection of Salmonella in milk samples and promising for routine use in the detection of Salmonella in milk.     

免疫磁性微球预处理结合超高效液相色谱-串联质谱法快速检测花生和花生油中黄曲霉毒素B1

目的设计并合成一种功能化免疫磁性微球,结合超高效液相色谱-串联质谱法(ultraperformance liquidchromatography-tandemmassspectrometry,UPLC-MS/MS)快速提取和检测花生和花生油中黄曲霉毒素B1(aflatoxin B1,AFB1)。方法样品经过甲醇-水溶液(70:30,V:V)提取,1.6 mg免疫磁性微球富集净化,用1.00 mL甲醇洗脱,采用Waters ACQUITY UPLC BEH C18色谱柱(50 mm×2.1 mm,1.7μm)分离,电喷雾离子源在正离子模式下分析AFB1的含量。结果该材料能够在15 min实现AFB1的快速提取净化。与UPLC-MS/MS联用,本方法的线性范围在0.1~50.0μg/L,检出限为0.04μg/kg,定量限为0.14μg/kg,相对标准偏差(relativestandard deviation,RSD)为2.2%。将本研究建立的方法用于检测花生及花生油中AFB1,方法回收率大于80%,重复性数据满足实验要求。与基于免疫亲和柱的国家标准方法进行了性能比较,结果与国家标准方法基本一致。结论该方法操作简单、用时短,可用于花生和花生油中AFB1的检测。