Colloidal gold-based immunochromatographic test strip for rapid detection of abrin in food samples

In the present study, we developed a convenient, rapid, and sensitive immunochromatographic (IC) test strip to detect abrin in assay buffer and spiked abrin in test food samples. The abrin IC test strip was based on a sandwich format consisting of a monoclonal antibody and a polyclonal antibody. The anti-abrin A chain monoclonal antibody from mice was immobilized on a porous nitrocellulose membrane as a capture antibody, while the anti-abrin polyclonal antibody from rabbits was conjugated to colloidal gold particles, serving as a detection antibody. Both visual observation and quantitative analysis indicated that the lower detection of the strip was about 3 ng/ml when abrin was directly spiked into milk, orange juice, and drinking water at a concentration of 3 to 60 ng/ml; the analytical recovery rate was 92.2 to 128%. With this method, abrin spiked into food could be detected in less than 10 min. Moreover, the IC test strip showed no cross-reaction with the closely related phytotoxin ricin. Therefore, our test strip is an ideal candidate for the development of a kit for rapid and quantitative detection of abrin in food samples.     

Application of two immunochromatographic test kits to screening of four kinds of allergic substances in imported foods

We tested for four kinds of allergic substances (egg, milk, wheat and peanuts) in 52 imported processed foods using immunochromatographic test kits (ITK). ELISA was also employed to confirm the effectiveness of the ITK. Among 92 data from 23 samples, allergic substances were detected in 9 cases with one kind of ITK, but not with the ELISA test. Among 116 data from 29 samples, 6 were negative with one kind of ITK and but positive with the other ITK. These results suggested that these 4 kinds of allergic substances in imported foods can be detected by using a double-check method with two kinds of ITK.     

胶体金免疫层析法快速检测食品中庆大霉素残留

应用胶体金免疫层析技术,建立一种快速检测食品中庆大霉素残留的方法。采用免疫竞争法,柠檬酸三钠还原制备胶体金颗粒,标记抗庆大霉素单克隆抗体并喷于玻璃纤维上,庆大霉素偶联抗原和羊抗兔二抗分别包被在硝酸纤维素薄膜表面作为检测线(T线)和控制线(C线),制备检测庆大霉素的胶体金免疫层析试纸条,并对试纸条的灵敏度、特异性、准确性和稳定性进行测定。测试结果表明:庆大霉素快速检测试纸条的灵敏度为0.7μg/mL,检测时间为10min,稳定性和特异性良好,与其他同类物质无交叉反应,其检测结果与酶联免疫吸附测定法(ELISA)检测结果呈现了很好的一致性。该方法快速简便、灵敏度高、特异性强、准确性和稳定性好,非常适合现场快速检测庆大霉素。      

胶体金免疫层析法快速检测食品中苏丹红I残留

通过设计合成苏丹红I衍生物,将其与明胶用混合酸酐法合成苏丹红I-明胶免疫抗原,免疫新西兰白兔制备抗苏丹红I多克隆抗体.采用柠檬酸三钠还原法制备颗粒大小为24.5 nm的胶体金,并制备苏丹红I-BSA抗原-胶体金复合物,组装检测试纸.实验结果表明,试纸条法的苏丹红I检测线为15 μg/kg,抗苏丹红I抗体与苏丹红Ⅱ、Ⅲ、Ⅳ均无交叉反应性,与高效液相测定差异不显著.检测时间5min,适用于食品中苏丹红I残留的快速检测.     

婴幼儿加工食品的强化

<正> 人体在不同的阶段会有不同的营养需求,如早产婴儿、手术后复原期的病人,为了满足其特殊的营养需要,可在食品中添加特定的营养素。营养素添加的类别食品的营养素添加可以分为复原、标准化和强化3类。复原,是指通过添加在食品加     

Rapid detection of Campylobacter jejuni using fluorescent microspheres as label for immunochromatographic strip test

Campylobacter jejuni is a worldwide foodborne pathogen recognized as a leading cause of human gastrointestinal enteritis. A rapid, sensitive, and specific method is required to monitor food and water in cases of contamination by this pathogen. This report presents a novel immunochromatographic test (ICT) using fluorescent microspheres labeled with polyclonal antibodies of C. jejuni as the capture reagent dispensed onto the conjugate pad. Polyclonal antibodies against the outer membrane protein PEB1 of C. jejuni were used as the detective reagent at the test line, whereas the goat anti-rabbit IgG was used on the control line. PEB1 was obtained by gene cloning and expression to prepare its antibody. In this study, a simple and rapid ICT is reported for detecting C. jejuni for the first time with a detection limit of 10⁶ CFU/ mL.     

Evaluation of two commercial lateral-flow test kits for detection of animal proteins in animal feed

Performance characteristics were evaluated for two lateral-flow test kits, Reveal for Ruminant in Feed (Neogen Corporation) and FeedChek (Strategic Diagnostics Inc.), designed to detect ruminant or terrestrial animal proteins in feeds. The stringent acceptance criteria used were developed by the Center for Veterinary Medicine Office of Research to identify test kits with comparable selectivity and sensitivity to microscopy and PCR assay, the analytical methods used by the U.S. Food and Drug Administration (FDA). Guidelines were developed for evaluating the selectivity, sensitivity, ruggedness, and specificity of these kits. These guidelines further stated that ruggedness and specificity testing would be performed only after a test passed both the selectivity and sensitivity assessments. Acceptance criteria for determining success were developed using a statistical approach requiring 90% probability of achieving the correct response, within a 95% confidence interval. A minimum detection level of 0.1% bovine meat and bone meal, consistent with the sensitivity of the methods used by the FDA, was required. Selectivity was assessed by testing 60 dairy feed samples that contained no added animal proteins; sensitivity was determined by evaluating 60 samples (per level of fortification) of the same feed that contained 0.025, 0.05, 0.1, 0.25, 0.5, 1, or 2% bovine meat and bone meal. The Reveal test passed the selectivity assessment but failed the sensitivity assessment, detecting only samples fortified at the 2% level and then only 17 to 33% of those samples, when read according to the label directions. The FeedChek test passed the sensitivity assessment but failed the selectivity assessment, with rates for false-positive results ranging from 34 to 38%, depending on the user. The sensitivity of the Reveal test was affected by the concentration of trace minerals present in the feed; concentrations toward the high end of the normal range prevented the detection of true positive feed samples containing bovine meat and bone meal. Better sensitivity assessments were obtained when lamb meal was used either alone or in combination with bovine meat and bone meal. The FeedChek test was not affected by the concentration of trace minerals or by the type of animal meal used. These results indicate that neither of the two tests is adequate for routine regulatory use.     

Evaluation of commercially available rapid test kits for the determination of oil quality in deep-frying operations

It is a challenging task to rapidly determine the quality of frying oils at various stages of frying. This study aims to evaluate the performance of eight different rapid test kits on three different types of oils, viz palm olein, cooking oil (a blend of palm olein, sesame oil and peanut oil) and sunflower oil. Two commonly consumed foods, French fries and chicken nuggets were selected as the frying food materials. Out of the eight test kits, five of them, namely FASafe™, 3M™ Low Range Shortening Monitor, Fritest®, Oxifrit-Test® and TPM Veri-Fry® were based on colorimetric reactions; whereas the other three test kits, namely Food Oil Monitor 310, Testo 265 and CapSens 5000 were based on dielectric constant. It was found that the test kits based on physical parameter provided more objective and valuable results as compared to those based on colorimetric reactions.     

免疫层析试纸条标记探针研究进展

免疫层析试纸条(Immunochromatographic test strips,ICTSs)有效结合了层析法卓越的分离能力和常规免疫分析技术的高度特异性,加之其便携性,该技术无疑为灵敏、定量现场检测提供了一个理想的平台。近年来随着检测方法和技术的不断革新,包括生色、发光及电化学信号产生型等在内的多种探针不断涌现,它们或直接共价结合靶标蛋白或装载于纳米颗粒中用于免疫层析试纸条的标记。本文旨在总结归纳当前ICTSs标记探针的最新进展,详尽解析各类探针性质、发展、优略势及其在生物分析中的应用,以期为研究者在设计试纸条时适宜探针的选择提供有力的技术支持。     

食品加工对过敏原活性的影响

近年来, 食物过敏性疾病的发病率明显上升, 已成为影响人类健康最常见的全球性疾病之一。本文对食品加工中常用的几种方法对特定食品过敏原活性的影响进行了综述, 这些加工方法包括热处理、高压处理、研磨、辐照、碱水解、梅拉德反应、酶解、微生物发酵和基因工程等, 并对存在的问题进行了分析。     

食品过敏原标签管理

食品过敏已引起了国际组织和世界各国家的高度重视,但由于食物的种类成千上万,各国家、各地区饮食习惯不同,机体对食物适应性的差异等导致致敏食物的不同。所以注意过敏原标识,远离含有过敏原的食品是预防和减少对消费者不良影响的方法之一。本文首先介绍对世界各国建立食品安全标准体系具有重要指导意义的食品法典委员会对过敏原标识的要求,继而系统性地介绍美国、欧盟、日本、韩国、加拿大、智利等国家参照其规定制定的过敏原标识管理法规、制度及存在的问题,最后对我国过敏原标识管理的现状进行考察,对我国过敏原管理提出建设性意见及建议。     

食品过敏原生物传感检测技术研究进展

食品过敏原已成为全球性的食品安全隐患。应对食品过敏反应最直接、有效的方法就是避免食用和接触各种含有致敏成分的食品。因此,快速和灵敏地检测食品中过敏原对预防和控制食品过敏反应是十分重要的。食品过敏原检测主要可以分为基于核酸和蛋白质的两大类检测技术。与基于聚合酶链式反应技术、液相色谱-串联质谱法的传统检测手段相比,生物传感技术检测平台因具有操作简单、高通量、灵敏度高、现场便携等优点,在食品过敏原快速检测领域备受关注。本文综述了近年来食品过敏原的生物传感检测技术研究进展,包括电化学传感器、光学传感器和其他新型传感器及其在食品过敏原检测中的应用,并展望了生物传感技术在食品过敏原分析中面临的挑战和发展趋势。     

Comparison of commercially available ELISA kits with human sera-based detection methods for peanut allergens in foods

Undeclared peanut allergens as contaminants in foodstuffs represent a major health problem for sensitized persons. Various immunochemical techniques are employed to detect and quantify peanut allergens. There is an urgent need to compare and standardize those test systems to enable comparable allergen analyses of foodstuffs, comparable studies, and consequent and consistent measures against the presence of hidden peanut allergens. The present study compared commercially available peanut ELISA kits with human sera-based immunoassay techniques (dot blotting and Western blotting), enabling semiquantitative and quantitative detection, and identification of peanut contaminants in foodstuffs. Additionally, the effect of conventional roasting conditions on the detection and quantification of peanut with the selected methods was investigated.