RT-PCR法检测贝类中的甲肝病毒的研究

在世界范围内,甲肝病毒是与食用贝类有关的主要传染性疾病之一。由于贝类中含有PCR抑制剂以及病毒富集过程中病毒的回收率低,阻碍了天然污染的贝类中HAV的PCR检测。研究中建立了一种经苷氨酸缓冲液洗涤,2次PEG沉降富集病毒,然后进行RNA提取和RT-PCR对贝类中的甲肝病毒进行检测的方法。经比较,采用小体系肠道样品检测比采用全贝检测的富集效果更佳,并比较了PEG8000和PEG6000对病毒富集的效果,回收率分别为13.5%和7.6%,此方法可有效地降低PCR抑制剂的影响,最低检测限可达10个TCID50/1.5 g。     

食源性致病菌鉴定技术的研究进展

食源性致病菌是影响食品安全的重要因素之一, 近年来食源性致病菌污染带来的食品安全事故不断被报道, 因此建立食源性致病菌的快速检测方法对食源性疾病控制至关重要。食源性致病菌的传统检测方法周期较长、检测步骤繁琐, 不适用于快速检测, 因而快速、简便、特异的检测方法成为研究的热点。本文主要从生化鉴定技术、分子生物学技术、免疫技术、代谢技术以及噬菌体鉴定技术等方面介绍目前国内外用于食品致病菌检测的技术, 并对这些技术进行分析和总结, 以期为今后进一步研究和开发新的检测技术提供参考。     

食源性致病菌鉴定技术研究进展

食源性致病菌是影响食品安全的重要因素之一,近年来食源性致病菌污染带来的食品安全事故不断被报道,因此建立食源性致病菌的快速检测方法对食源性疾病控制至关重要。食源性致病菌的传统检测方法周期较长、检测步骤繁琐,不适用于快速检测,因而快速、简便、特异的检测方法成为研究的热点。本文主要从生化鉴定技术、分子生物学技术、免疫技术、代谢技术以及噬菌体鉴定技术等方面介绍目前国内外用于食品致病菌检测的技术,并对这些技术进行分析和总结,以期为今后进一步研究和开发新的检测技术提供参考。     

草莓中甲型肝炎病毒检测

目的：建立草莓中甲型肝炎病毒（hapatitis A virus,HAV）的有效富集方法及病毒RNA提取方法,用于草莓中HAV检测。方法：利用甲肝减毒疫苗对已知阴性的草莓样品进行人工污染,通过有效富集条件的优化及RNA提取后,采用实时荧光逆转录-聚合酶链式反应进行检测。结果：病毒富集选择Tris-甘氨酸-1 g/100 mL牛肉浸提物缓冲液洗脱、果胶酶30 U、氯仿-正丁醇为抑制剂去除剂、聚乙二醇沉淀、5 ℃孵育1 h等优化条件,检测灵敏度较高;最优RNA提取方法为美国ABI公司生产的RNA提取试剂盒。采用优化后的方法对草莓样品中HAV病毒的检测显示,该病毒粒子的检测灵敏度可以达31.36 CCID50/20 g样品。同时对50 份送检样品进行检测,结果均为阴性。结论：所建立的病毒富集方法和核酸提取方法更适合草莓样品中HAV的检测,灵敏度较高。     

电化学和光纳米探针技术用于重金属离子快速检测的研究进展

随着现代工业的快速发展,重金属污染问题日益严重,对人类健康造成了严重威胁,因此发展快速、灵敏、准确、易携带的重金属离子检测方法至关重要。电化学分析作为一种特殊的化学分析方法,因其选择性好、操作安全、分析简便的优点被应用于食品检测、环境监测、生物医疗各方面。光纳米探针技术在检测分析物质时,具有灵敏度高、选择性好、操作简便的优点。电化学分析法和光纳米探针技术在检测重金属离子时,克服了传统重金属方法检测流程繁琐、检测成本高、操作过程复杂、操作要求高的不足,成为当前重金属离子快速检测的研究热点。本文对重金属污染现状、电化学和光纳米探针技术检测重金属的原理以及研究进展进行阐述,并对其未来发展趋势进行展望。     

日本首次发现H5N8型禽流感病毒

正日本农林水产省17日宣布,最近在九州岛熊本县养鸡场出现的禽流感疫情,经检测确认是H5N8型禽流感病毒所导致,这是日本首次确认发现该病毒。不过农林水产省认为,由于当地已经完成了防疫措施,今后感染进一步扩大的危险性很低。熊本县政府13日宣布,该县多良木町的养鸡场在11日和12日有270只鸡死亡,有可能发生了高致病性禽流感。研究人员对10只死鸡进行检测后,确认其中两只死鸡感染了H5型禽流感病毒。     

饮用水生物性污染物快速检测技术研究进展

饮用水微生物安全问题大多源于细菌、病毒、原生动物和藻类等生物性污染。加强饮用水生物性污染物的检测与监测, 防止消费者饮用存在生物性污染的水, 对保障饮用水的生物性安全具有十分重要的意义。当前饮用水微生物检测工作中, 主要采用国标检测方法对4项常规微生物及2项非常规微生物指标进行检测, 存在指标覆盖不全、耗时较长、操作复杂等不足, 难以满足饮用水生物性污染物监测的现实需求。因此, 本文重点对饮用水生物性污染物的各种快速检测与筛查技术, 如微生物快速测试片检测技术、生物荧光检测技术、流式细胞仪检测技术、PCR检测技术、等温扩增检测技术、基因芯片检测技术、高通量测序检测技术等进行综述、比较与探讨, 以期为饮用水中生物性污染物快速检测与筛查提供适宜的技术参考基础。     

乳品真菌污染及快速检测技术研究进展

真菌及其所产危害物已成为食品中最为严重的污染之一。文章主要就近年来乳及乳制品中真菌污染概况以及真菌快速检测技术相关研究进行概述,对比传统检测方法和快速检测技术在乳品应用概况,可通过进一步改进快速检测技术体系及开发新型检测体系,更好地监控乳品质量,推动乳品行业持续健康发展。     

等温扩增技术在食源性致病菌检测中的研究进展

食源性致病菌污染是影响食品质量安全的重要因素之一,加强食源性致病菌的检测力度对于保证食品安全以及预防食源性疾病至关重要。基于核酸的分子检测技术较传统的培养方法相比,更加快速、灵敏、高效。等温扩增技术以反应条件简单等优点逐渐替代变温扩增技术。该文简述了环介导等温扩增、链替代等温扩增、单引物等温扩增、滚环等温扩增以及跨越式滚环等温扩增5种技术的研究进展及其在食源性致病菌快速检测方面的应用,指出了等温扩增反应存在的共性问题,并提出解决措施。此外,还对这5种等温扩增技术进行比较分析,为食源性致病菌的现场快速检测与筛查提供参考依据。     

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临床诊断、食品安全等领域的研究热点。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。     

Foodborne viruses: an emerging problem

Several groups of viruses may infect persons after ingestion and then are shed via stool. Of these, the norovirus (NoV) and hepatitis A virus (HAV) are currently recognised as the most important human foodborne pathogens with regard to the number of outbreaks and people affected in the Western world. NoV and HAV are highly infectious and may lead to widespread outbreaks. The clinical manifestation of NoV infection, however, is relatively mild. Asymptomatic infections are common and may contribute to the spread of the infection. Introduction of NoV in a community or population (a seeding event) may be followed by additional spread because of the highly infectious nature of NoV, resulting in a great number of secondary infections (50% of contacts). Hepatitis A is an increasing problem because of the decrease in immunity of populations in countries with high standards of hygiene. Molecular-based methods can detect viruses in shellfish but are not yet available for other foods. The applicability of the methods currently available for monitoring foods for viral contamination is unknown. No consistent correlation has been found between the presence of indicator microorganisms (i.e. bacteriophages, E. coli) and viruses. NoV and HAV are highly infectious and exhibit variable levels of resistance to heat and disinfection agents. However, they are both inactivated at 100 degrees C. No validated model virus or model system is available for studies of inactivation of NoV, although investigations could make use of structurally similar viruses (i.e. canine and feline caliciviruses). In the absence of a model virus or model system, food safety guidelines need to be based on studies that have been performed with the most resistant enteric RNA viruses (i.e. HAV, for which a model system does exist) and also with bacteriophages (for water). Most documented foodborne viral outbreaks can be traced to food that has been manually handled by an infected foodhandler, rather than to industrially processed foods. The viral contamination of food can occur anywhere in the process from farm to fork, but most foodborne viral infections can be traced back to infected persons who handle food that is not heated or otherwise treated afterwards. Therefore, emphasis should be on stringent personal hygiene during preparation. If viruses are present in food preprocessing, residual viral infectivity may be present after some industrial processes. Therefore, it is key that sufficient attention be given to good agriculture practice (GAP) and good manufacturing practice (GMP) to avoid introduction of viruses onto the raw material and into the food-manufacturing environment, and to HACCP to assure adequate management of (control over) viruses present during the manufacturing process. If viruses are present in foods after processing, they remain infectious in most circumstances and in most foods for several days or weeks, especially if kept cooled (at 4 degrees C). Therefore, emphasis should be on stringent personal hygiene during preparation. For the control of foodborne viral infections, it is necessary to: Heighten awareness about the presence and spread of these viruses by foodhandlers; Optimise and standardise methods for the detection of foodborne viruses; Develop laboratory-based surveillance to detect large, common-source outbreaks at an early stage; and Emphasise consideration of viruses in setting up food safety quality control and management systems (GHP, GMP, HACCP).     

Emerging Spectroscopic and Spectral Imaging Techniques for the Rapid Detection of Microorganisms: An Overview

Microorganism contamination and foodborne disease outbreaks are of public concern worldwide. As such, the food industry requires rapid and nondestructive methods to detect microorganisms and to control food quality. However, conventional methods such as culture and colony counting, polymerase chain reaction, and immunoassay approaches are laborious, time‐consuming and require trained personnel. Therefore, the emergence of rapid analytical methods is essential. This review introduces 6 spectroscopic and spectral imaging techniques that apply infrared spectroscopy, surface‐enhanced Raman spectroscopy, terahertz time‐domain spectroscopy, laser‐induced breakdown spectroscopy, hyperspectral imaging, and multispectral imaging for microorganism detection. Recent advances of these technologies from 2011 to 2017 are outlined. Challenges in the application of these technologies for microorganism detection in food matrices are addressed. These emerging spectroscopic and spectral imaging techniques have the potential to provide rapid and nondestructive detection of microorganisms. They should also provide complementary information to enhance the performance of conventional methods to prevent disease outbreaks and food safety problems.     

Improvement of Procedure for HAV Detection in Bottled Water

Hepatitis A virus (HAV) is responsible for around half of the total number of hepatitis infections diagnosed worldwide. HAV infection is mainly propagated via the fecal–oral route, and as a consequence of globalization, foodborne outbreaks are reported with increasing frequency. A future standard (CEN/TC 275/WG6/TAG4) for norovirus and HAV detection in food will consider bottled water as a food product; therefore, a validated method for routine monitoring of HAV in bottled water is required. In this study, we describe the validation of a procedure to monitor and quantify HAV in bottled water samples by real-time RT-PCR. Initial experiments focused on evaluating the elution conditions suitable for HAV release from positively charged membrane. Finally, elution with 50 mM glycine and 1 % beef extract (pH 9.5), using an ultrasound cleaning bath, and concentration by ultrafiltration were the methods selected to evaluate HAV detection limit in different types of bottled waters. The HAV detection limit was determined between 0.2 and 20 TCID₅₀/L of bottled water depending on the composition of the bottled water, which highlights the importance of evaluating different types of bottled waters when a method has to be standardized.     

Processing Strategies to Inactivate Hepatitis A Virus in Food Products: A Critical Review

Hepatitis A infection, caused by hepatitis A virus (HAV), is the leading cause of human viral hepatitis throughout the world and is mainly propagated via the fecal–oral route. Transnational outbreaks of food‐borne infections are reported with increasing frequency as a consequence of international food trade. Food‐borne outbreaks caused by HAV are mainly associated with bivalve molluscs, produce (soft fruits and leafy greens), and ready‐to‐eat meals. The purpose of this paper was to conduct a structured and systematic review of the published literature on the current state of knowledge regarding the stability of HAV in foods as well as the efficacy of food processing strategies and to identify and prioritize research gaps regarding practical and effective mechanisms to reduce HAV contamination of foods. In particular, processing and disinfection strategies for the 3 food categories have been compiled in this review, including common and emerging food technologies. Overall, most of these processes can improve food safety; however, from a commercial point of view, none of the methods can guarantee total HAV inactivation without affecting the organoleptic qualities of the food product.     

下一代测序技术在食源性致病菌研究中的应用

下一代测序技术是DNA测序的一项革命性创新技术,其特点是方便快速、高效准确、信息容量大,可实现物种基因组或转录组的深入研究。现阶段,食源性致病微生物导致的全球食品安全问题不断发生,下一代测序技术可在信息缺乏或多种微生物存在的情况下对食源性致病微生物进行检测判定,可在基因序列的背景下更科学地认识食源性致病菌的遗传特性、代谢能力、致病机制等,为食源性微生物疾病预防和控制提供重要的依据。本文主要介绍了在第一代测序技术的基础上发展起来的下一代测序技术,包括第二代测序技术和第三代测序技术的原理、发展历程及优劣势,着重概述了下一代测序技术在食源性致病菌检测鉴定中的应用,并展望该技术在食源性致病菌检测应用中的发展趋势。     

免疫磁分离技术在食源性致病菌快速检测中的研究进展

建立食源性致病菌快速高效的检测新方法和策略对控制食源性疾病的爆发至关重要。样品前处理是快速筛选病原体的关键步骤。常规食源性致病菌检测技术通常需要前增菌和选择性分离等预处理过程才能达到提高目标细菌浓度的目的,耗时长且灵敏度低。免疫磁分离技术（immunomagnetic separation,IMS）是一种能够在较短时间内从复杂食品样品中分离和浓缩目标病原菌的技术,已被应用于多种食源性致病菌的检测。本文综述了IMS在食源性致病菌检测中的应用,重点阐述了IMS作用原理、影响IMS效果的因素以及结合其他检测技术在食源性致病菌快速检测中的最新应用研究,以期为该技术更深层次的应用研究和我国食品安全快速检测技术的发展提供理论支持。