表面等离子共振技术快速检测食品中的 玉米赤霉烯酮毒素

目的建立基于表面等离子共振(surface plasmon resonance,SPR)技术快速检测食品中玉米赤霉烯酮毒素(zearalenone,ZEN)的方法。方法采用表面自组装技术(self-assembled monolayer,SAM)在金膜的表面修饰羧基基团,将ZEN抗原与牛血清白蛋白(albumin from bovine serum,BSA)偶联物(ZEN-BSA)通过共价键固定在芯片的表面,采用竞争法检测样品中的玉米赤霉烯酮毒素。结果该方法的检测限为8.2 ng/m L,ZEN单克隆抗体与呕吐毒素、黄曲霉毒素B_1、赭曲霉毒素、伏马毒素等没有交叉反应,与α-玉米赤霉烯醇和β-玉米赤霉烯醇交叉反应率分别为15.3%和11.5%。结论本方法具有简便、快速和高灵敏度等优势,在食品中真菌毒素的快速检测方面具有潜在的应用价值。     

LSPR-based colorimetric biosensing for food quality and safety

Ensuring consistently high quality and safety is paramount to food producers and consumers alike. Wet chemistry and microbiological methods provide accurate results, but those methods are not conducive to rapid, onsite testing needs. Hence, many efforts have focused on rapid testing for food quality and safety, including the development of various biosensors. Herein, we focus on a group of biosensors, which provide visually recognizable colorimetric signals within minutes and can be used onsite. Although there are different ways to achieve visual color-change signals, we restrict our focus on sensors that exploit the localized surface plasmon resonance (LSPR) phenomenon of metal nanoparticles, primarily gold and silver nanoparticles. The typical approach in the design of LSPR biosensors is to conjugate biorecognition ligands on the surface of metal nanoparticles and allow the ligands to specifically recognize and bind the target analyte. This ligand–target binding reaction leads to a change in color of the test sample and a concomitant shift in the ultraviolet-visual absorption peak. Various designs applying this and other signal generation schemes are reviewed with an emphasis on those applied for evaluating factors that compromise the quality and safety of food and agricultural products. The LSPR-based colorimetric biosensing platform is a promising technology for enhancing food quality and safety. Aided by the advances in nanotechnology, this sensing technique lends itself easily for further development on field-deployable platforms such as smartphones for onsite and end-user applications.     

State of the art: Lateral flow assays toward the point-of-care foodborne pathogenic bacteria detection in food samples

Diverse chemicals and some physical phenomena recently introduced in nanotechnology have enabled scientists to develop useful devices in the field of food sciences. Concerning such developments, detecting foodborne pathogenic bacteria is now an important issue. These kinds of bacteria species have demonstrated severe health effects after consuming foods and high mortality related to acute cases. The most leading path of intoxication and infection has been through food matrices. Hence, quick recognition of foodborne bacteria agents at low concentrations has been required in current diagnostics. Lateral flow assays (LFAs) are one of the urgent and prevalently applied quick recognition methods that have been settled for recognizing diverse types of analytes. Thus, the present review has stressed on latest developments in LFAs-based platforms to detect various foodborne pathogenic bacteria such as Salmonella, Listeria, Escherichia coli, Brucella, Shigella, Staphylococcus aureus, Clostridium botulinum, and Vibrio cholera. Proper prominence has been given on exactly how the labels, detection elements, or procedures have affected recent developments in the evaluation of diverse bacteria using LFAs. Additionally, the modifications in assays specificity and sensitivity consistent with applied food processing techniques have been discussed. Finally, a conclusion has been drawn for highlighting the main challenges confronted through this method and offered a view and insight of thoughts for its further development in the future.     

Synthesis and stability analysis of papain-functionalized gold nanoparticles (P-AuNPs) for the colorimetric detection of mercury in milk

To detect mercury in dairy cow milk by colorimetric techniques, papain-functionalized gold nanoparticles (P-AuNPs) were synthesised. Papain-functionalized gold nanoparticles aggregated when mercury ions were introduced, causing their absorption peak to shift from 525 to 575 nm. Dynamic light scattering and transmission electron microscopy determined that aggregated P-AuNPs average sizes were 26.60 nm and 15.17–18.23 nm, respectively, with monodispersed. The detection limit of P-AuNPs for mercury in milk samples was 1.0 ppm with high recovery. This sensor showed relatively high selectivity and sensitivity towards Hg²⁺ ions in milk. This method shows utility in developing countries for monitoring the concentration of Hg²⁺ in water, milk and food items for safety purposes.     

基于纳米金粒子的猪源性成分快速比色检测

目的 开发一种基于纳米金粒子快速比色的猪源性成分快速检测方法。方法 选取猪线粒体基因中特异性DNA片段为靶点, 利用互补单链DNA与纳米金粒子偶联为探针, 提取检测目标DNA后在盐溶液中进行检测。结果 探针上DNA结合检测目标后, 纳米金粒子失去单链DNA的保护, 发生聚集, 由红色变为蓝色, 实现裸眼可视检测。核酸偶联的最佳用量为0.1 mmol/L的核酸添加30 μL, 方法的检出限为5%。 结论 这种比色检测可以在不使用复杂仪器的条件下将猪肉与其牛肉类产品区分开来, 方法快捷迅速, 对肉制品掺假的防控具有重要意义。     

食源性致病菌和腐败菌的快速检测方法研究进展

食源性致病菌和腐败菌污染一直是引发食品安全事件的重要因素。传统的检测方法虽具有较高的准确性,但需培养及生化实验,耗费时间长且操作较复杂,开发高效、快速的检测方法对保障食品安全至关重要。近年来,科学技术的进步使一些新方法、新技术逐渐被运用,比传统培养法检测时间更短、效率更高、特异性更好,具有广阔的应用前景。因此,本文综述了食源性致病菌和腐败菌快速检测方法的最新研究进展,包括纸片法、流式细胞术、阻抗法、腺苷三磷酸荧光法、光谱检测技术、分子生物学检测技术、免疫学检测法及生物传感器检测技术等,着重论述了各种方法的原理、优缺点、应用状况及发展方向,为致病菌和腐败菌引发的食品安全事件的预防及控制提供参考。     

Rapid colorimetric detection of proteins and bacteria using silver reduction/precipitation catalyzed by gold nanoparticles

A colorimetric immunoassay has been developed based on the reduction and precipitation of silver ions catalyzed by colloidal gold. This method was evaluated for a noncompetitive heterogeneous immunoassay to detect ovalbumin as a model protein and Escherichia coli as model bacterium. The influence of relevant experimental variables, including the reaction time of antigen with antibody, the dilution ratio of the colloidal gold-labeled protein, time allowed for silver reduction/precipitation reaction and other parameters were examined and optimized. This colorimetric method of detection is convenient, easy to use and economic. The presence of the target molecules or antigens can be visually inferred based on the color change that occurs in a short time without using major instrumentation. This method is widely amenable for detection of proteins, viruses and bacteria.     

金纳米粒子在食源性病原体检测中的应用研究进展

近年来,由食源性病原体污染食物导致中毒或死亡事件在全球频发,食源性病原体引起的疾病已成为危害人类健康的头号杀手,亟需开发快速、准确且灵敏的食源性病原体检测方法用于日常的食源疫情监测和预防食源性疾病暴发。金纳米粒子凭借其小尺寸、表面积大、高反应活性及易于与其他传统检测方法相结合等优势成为食品安全检测领域的研究热点。本文在总结了金纳米粒子的理化性质、制备的基础上,重点综述了基于金纳米粒子的免疫标记技术在食源性病原体检测方面的应用,主要涉及免疫层析技术、比色法、生物传感器的制备和探针技术等的最新研究进展,并对未来研究方向进行了展望,以期为临床样本或食物中的食源性病原体检测快速化、准确化提供理论依据。     

金纳米粒子在食品检测领域中的研究进展

随着纳米技术的快速发展,作为纳米材料中化学性质最稳定的金纳米粒子,以其独特地光学、电学性质和良好地生物兼容性广泛的被应用于食品检测领域。文章综述了金纳米粒子在食品检测领域的最新研究进展,讨论了金纳米粒子在当前食品安全与检测领域的优势和不足,并对金纳米粒子在食品检测领域的未来发展趋势做了展望。      

基于局域表面等离子共振的比色法用于食品质量安全检测的研究进展

局域表面等离子体共振(localized surface plasmon resonance,LSPR)是表面等离子共振(surface plasmon resonance,SPR)中的一种特殊情况,是当光线入射到金属纳米颗粒上时引起的共振现象,可被用来实时跟踪天然状态下生物分子之间的相互作用.这种方法对生物分子无任何...     

用于发酵肉中菌种的优选

根据肉制品发酵剂的基本要求,对植物乳杆菌(Lp)、干酪乳杆菌(Lc)、瑞士乳杆菌(Lh)、嗜热链球菌(St)、乳酸乳球菌(Pl)、嗜酸乳杆菌(La)和德氏乳杆菌(Ld))进行了优选试验.结果表明:当NaCl的浓度达到6%时,植物乳杆菌、干酪乳杆菌、嗜酸乳杆菌和德氏乳杆菌还能正常生长,当耐亚硝酸盐浓度达到150mg/kg时,植物乳杆菌、干酪乳杆菌和嗜酸乳杆菌还能正常生长.但干酪乳杆菌的产酸性能要优于植物乳杆菌和嗜酸乳杆菌,所有供试的乳酸菌都没产气、产氨、产H2S的性质,也没有分解蛋白质和脂肪的性质.     

Combating biofilms of foodborne pathogens with bacteriocins by lactic acid bacteria in the food industry

Most foodborne pathogens have biofilm-forming capacity and prefer to grow in the form of biofilms. Presence of biofilms on food contact surfaces can lead to persistence of pathogens and the recurrent cross-contamination of food products, resulting in serious problems associated with food safety and economic losses. Resistance of biofilm cells to conventional sanitizers urges the development of natural alternatives to effectively inhibit biofilm formation and eradicate preformed biofilms. Lactic acid bacteria (LAB) produce bacteriocins which are ribosomally synthesized antimicrobial peptides, providing a great source of nature antimicrobials with the advantages of green and safe properties. Studies on biofilm control by newly identified bacteriocins are increasing, targeting primarily onListeria monocytogenes, Staphylococcus aureus, Salmonella, and Escherichia coli. This review systematically complies and assesses the antibiofilm property of LAB bacteriocins in controlling foodborne bacterial-biofilms on food contact surfaces. The bacteriocin-producing LAB genera/species, test method (inhibition and eradication), activity spectrum and surfaces are discussed, and the antibiofilm mechanisms are also argued. The findings indicate that bacteriocins can effectively inhibit biofilm formation in a dose-dependent manner, but are difficult to disrupt preformed biofilms. Synergistic combination with other antimicrobials, incorporation in nanoconjugates and implementation of bioengineering can help to strengthen their antibiofilm activity. This review provides an overview of the potential and application of LAB bacteriocins in combating bacterial biofilms in food processing environments, assisting in the development and widespread use of bacteriocin as a promising antibiofilm-agent in food industries.     

利用表面等离子共振技术快速检测牛奶中的磺胺甲噁唑

利用表面等离子共振(SPR)技术,建立快速定量检测牛奶中磺胺甲噁唑(SMX)的方法。将SMX共价偶联到表面等离子共振芯片表面,并对抗体的结合浓度及芯片的再生条件进行优化,检测芯片的稳定性。在无抗牛奶中添加系列质量浓度的SMX,利用免疫竞争抑制原理构建标准曲线,并对市售18个牛奶样品进行检测。结果表明:制备的芯片稳定,90个循环相对标准偏差(RSD)为1.23%;该方法的检测限为3.2ng/mL;18个牛奶产品中16个SMX的残留量在规定的允许范围内。所建立的方法可以在15min内完成样品的前处理和检测,是一种简便快捷的定量检测方法。     

食品中产组胺微生物及其控制的研究进展

组胺是食品中游离组氨酸经组氨酸脱羧酶分解产生的一种胺类物质,也是一些出口水产食品中一项重要的质量检测指标。分析比较了国内外几类易产组胺食品中的产组胺微生物分布情况,并综述了组胺形成和控制方法的研究进展,由此可为食品中组胺的预防及控制提供基础,以确保食品的安全性。     

乳制品中常见食源性致病菌检测技术的研究进展

近年来频繁发生的乳与乳制品的质量安全事件引起了人们对乳制品安全的普遍关注,而食源性致病菌污染是乳制品安全问题的重要隐患之一。乳制品中常见的食源性致病菌有沙门氏菌、蜡样芽孢杆菌、阪崎肠杆菌、李斯特菌和志贺氏菌等。目前食源性致病菌的检测技术主要有国家标准中的培养法检测技术、分子生物学技术和免疫学技术,分子生物学技术中的PCR检测技术因具有特异性和灵敏度高、简便、快速等优点而得以广泛应用。本文对国家标准中的常规检测技术、分子生物学技术和免疫学技术在乳制品中常见食源性致病菌检测领域的应用进展进行了介绍,并对其影响因素及存在的问题进行了简要阐述。     

The inhibitory effect of plant essential oils on foodborne pathogenic bacteria in food

Abstract

In recent years, with the continuous improvement of people's living standard, the importance of healthy lifestyles is becoming more and more recognized. Therefore, food safety has attracted much attention. This has prompted people to study new technologies that can guarantee food safety without the use of preservatives. Compared with other types of food preservatives, essential oils (EOs) are gotten more attention, because they meet the current development trend of food additives about "green", "safety" and "health". Therefore, this paper focuses on the research of effective contribution of EOs to inhibit the growth of foodborne pathogens, systematically summarized the commonly used EOs and their main extraction methods and chemical components and, the antibacterial mechanism of EOs on food borne pathogens, systematically analysis the specific application case of EOs in food discussed. Hoping to provide some reference and help to the relevant researchers.     

牛乳中嗜冷菌危害及其检测方法研究进展

虽然低温保藏及冷链技术限制了牛乳中微生物的繁殖与代谢,但是在低温环境中恰恰非常适合嗜冷菌的生长代谢,并影响牛奶质量。生产中通常用巴氏杀菌和超高温灭菌来杀灭牛奶中的嗜冷菌,却无法消除由嗜冷菌所分泌的较高的耐热性的脂肪酶和蛋白酶,进一步影响乳及乳制品风味质地。因此快速检测牛乳中的嗜冷菌,对于控制生牛乳中嗜冷菌繁殖、提高乳制品产品质量、延长货架期等都具有重要的现实意义。本文主要总结与讨论了牛乳中嗜冷菌的危害以及几种常见的对原料奶中嗜冷菌快速检测的方法,包括直接荧光过滤技术、电阻抗法、酶联免疫吸附法、流式细胞计数法、氨肽酶法、聚合酶链反应结合酶联免疫吸附法,并将它们在工业应用上的优缺点进行了比较,并对此领域的技术发展方向给予展望。     

速测盒法快速测定肉及肉制品中亚硝酸盐

目的 了解亚硝酸盐速测盒的可靠性,为现场监督执法及基层快速检测提供有力的技术支撑。方法采用速测盒方法检测亚硝酸盐标准溶液、肉及肉制品中亚硝酸盐添加情况,并与《GB 5009.33-2016食品中亚硝酸盐与硝酸盐的测定》第二法(盐酸萘乙二胺法)进行对比。结果速测盒对亚硝酸盐最低检出限可达到0.1 mg/L;检测样品时,速测盒与盐酸萘乙二胺法阴性符合率为97.8%,阳性符合率为100.0%。不同环境温度下,只需将反应时间控制在5 min以上,则不会对检测结果产生影响。样品经简单处理后,显色剂滴加到样品提取液中,混匀后反应3～5 min,即可观察结果。检测单个样品20 min内即可出结果。结论速测盒法具有快速、准确、方便、灵敏等特点,适用于肉及肉制品中亚硝酸盐现场定性分析。