定点屠宰场（点）猪肉中三种主要食源性致病菌污染情况调查

为了解本地生猪定点屠宰场(点)猪肉中的沙门氏菌、大肠杆菌O157:H7、单增李斯特菌3种食源性致病菌污染情况,对10个场(点)出场的猪肉进行抽样,采用沙门氏菌测试片、大肠杆菌O157:H7测试片及李斯特菌检测板进行快速检测,再用国标法对快速检测出的阳性样品进行复检鉴定。结果显示:50份样本中,检出沙门氏菌阳性7份,阳性检出率为14%;20份样本中,检出大肠杆菌O157:H7阳性1份,阳性检出率为5%,检出单增李斯特菌阳性5份,阳性检出率为25%。此外,还发现样本中存在细菌的混合污染,其中沙门氏菌和单增李斯特菌双阳性2份,3种菌全阳性1份。调查结果表明:本地屠宰场出场猪肉中,这3种主要食源致病菌污染情况较严重,特别是小型屠宰点,应引起监管部门重视,加快推进屠宰企业转型升级;快速测试片的检测结果准确性偏低,特异性差,需要尽快建立一种快速特异的检测方法,用于屠宰场的致病菌快速检测。     

2014年呼和浩特市食源性致病菌监测结果分析

为了了解呼和浩特地区主要食品中食源性致病菌的污染状况,给食源性疾病的预防控制提供科学依据,本文对2014年所采集的277份样品进行检测分析,检测结果为阳性样品21份,检出率为7.58%;检出阳性菌株22株,阳性菌株检出率为3.06%。检出阳性样品的食品类别为调理肉制品、生食肉类、婴幼儿配方食品、冷冻肉糜制品、巴氏杀菌乳、学生午餐和冷冻鱼糜制品7大类,其中调理肉制品、生食肉类阳性样品检出率最高,达到了50%。有阳性检出的致病菌为单核细胞增生李斯特氏菌、阪崎肠杆菌、蜡样芽孢杆菌及金黄色葡萄球菌,检出率分别为7.19%、6.67%、6.45%及1.89%。     

3种食源性细菌免疫磁珠联合ATP发光检测技术研究

沙门氏菌、单核细胞增生李斯特菌和金黄色葡萄球菌是食品中常见的致病菌,在国内外常引起食源性疾病。为解决食源性疾病中的微生物检测问题,本研究将免疫磁珠技术和ATP发光技术联合用于食品微生物检测,选择沙门氏菌、单核细胞增生李斯特菌病和金黄色葡萄球菌为检测对象,建立快速检测这3种常见食源性病原菌的富集及检测新方法。该方法在显著缩短预增菌时间的条件下,通过免疫磁珠的富集作用获得与常规增菌时间同样的效果,样品中的微生物浓度增加了10倍,大大提高了样本检出率,缩短了检测周期。结果表明,本研究建立的免疫磁珠富集后联合ATP发光技术具有快速、敏感、特异和低廉的优点,可用于检测食品中沙门氏菌、单核细胞增生李斯特菌以及金黄色葡萄球菌,具有较好的推广应用前景。     

乌鲁木齐市屠宰场三种食源性细菌的污染情况调查

为了解乌鲁木齐市冬季不同畜禽屠宰场屠宰加工环节中大肠杆菌O157:H7、沙门氏菌、单增李斯特菌的污染情况。采集羊、牛、猪、鸡屠宰场的肉、环境拭子样本100份,按食品安全国家标准中的相关食品微生物学检验方法进行检测。结果共检出沙门氏菌11株,检出率为11%;检出单增李斯特菌2株,检出率为2%;没有检测出大肠杆菌O157:H7。调查结果表明乌鲁木齐市冬季屠宰中场沙门氏菌的污染主要存在于猪、鸡屠宰场的屠宰工具、传送带等环境中,单增李斯特菌存在于羊屠宰场的羊肉和环境中。各相关部门应加强屠宰场监管力度,以降低食品安全问题发生的可能。     

广东10个屠宰场猪肉中3种食源性致病菌的检测

为了解肠出血性大肠埃希氏菌O157:H7、沙门氏菌和空肠弯曲菌等3种食源性致病菌在生猪屠宰场的污染情况。采集广东惠州和清远两地共10家生猪屠宰场498头猪肉样品,分别经改良EC新生霉素增菌肉汤、SC(亚硒酸盐胱氨酸增菌液)和Bolton肉汤增菌,用大肠埃希氏菌O157:H7、沙门氏菌和空肠弯曲菌的特异性引物进行PCR扩增及测序检测,阳性菌液再分别涂抹于山梨醇麦康凯平板、DHL(胆硫乳琼脂)和Skirrow血琼脂,挑取疑似菌落再次PCR验证,计算检出率。结果显示,检出大肠埃希氏菌O157:H7阳性样本2份,检出率0.4%,检出沙门氏菌阳性样本70份,检出率14.06%,空肠弯曲菌未检出。结果表明,惠州和清远两地屠宰场均存在食源性致病菌污染情况,其中沙门氏菌污染较为严重,惠州地区检出率高于清远地区。提示屠宰场应加强屠宰过程中环境和加工用具的消毒,以保证屠宰环节的食品安全。     

免疫层析技术在食源性细菌检测中的应用及优化

目前食品安全问题已经成为国家和社会关注的一项重点问题,食源性致病菌是引发食源性疾病的最主要因素。在全球各地均曾报道食源性致病菌如沙门氏菌、大肠杆菌、金黄色葡萄球菌和单核细胞增生李斯特氏菌等引起的食源性疾病事件。建立快速、准确检测食源性致病菌的方法是预防和控制相关疾病的前提。免疫层析技术在各个领域中发展迅速,应用广泛。文章主要综述了免疫层析技术在食源性细菌检测中的应用及该技术的优化方法,以期为今后开发快速检测技术提供理论支持。     

动物与食物源病原菌的联系、健康影响及现状

生产人类蛋白食物的动物是许多食源性病原体的主要宿主,如弯曲杆菌、肠道沙门氏菌、大肠杆菌的和单核增生李斯特菌。本文综述了动物与食源性致病菌(如沙门氏菌、弯曲杆菌、志贺产毒素大肠杆菌)和单核细胞增生素的联系以及其影响和现状。这些致病菌将继续广泛的爆发和引起动物死亡,因为目前没有有效的干预措施将它们从动物和食品中消除。     

7种食源性致病菌GeXP多重PCR检测方法的建立及其应用

本研究旨在建立一种能够同时鉴别包括大肠杆菌O157：H7、沙门菌、空肠弯曲菌、单核细胞增生李斯特菌、霍乱弧菌、副溶血弧菌和金黄色葡萄球菌7种常见食源性致病菌的GeXP多重PCR检测方法。根据这些致病菌在GenBank上公布的保守基因序列,设计合成了7对特异性GeXP引物。用单一或混合细菌样品的DNA模板优化反应条件,设置对照组,构建重组质粒,随机组合不同浓度的样品,验证所建立的GeXP方法的特异性、敏感性和准确性。最后用该方法检测120份临床样品,进一步验证所建立的GeXP检测方法的准确性和可靠性。结果显示,单一或混合模板的GeXP检测均能特异性出现相应清晰峰值,可在10³拷贝·μL^-1水平上同时特异地检测出7种细菌病原体,不同浓度模板混合时,本试验所建立的方法依然可检测出对应病原体。检测120份临床样品,GeXP多重PCR阳性率为2.50%（3/120）~15.83%（19/120）,普通PCR阳性率为2.50%（3/120）~15.00%（18/120）,GeXP多重PCR多检出8份阳性,表明GeXP方法更为敏感与准确。本研究建立的同时鉴别7种食源性致病菌的GeXP多重PCR检测方法,具有高通量、特异性强和敏感性高的特点,为食源性常见致病菌感染或混合感染提供了快速分子诊断方法。     

乳及乳制品中食源性致病菌快速检测技术的应用研究进展

由于乳制品营养丰富,为金黄色葡萄球菌、沙门氏菌、单核细胞增生李斯特菌、克罗诺杆菌等食源性致病菌提供了良好的生长环境,严重威胁乳制品相关的食品安全,因此对乳制品中食源性致病菌进行快速、准确检测是防治和检测食源性致病菌工作中必不可少的环节。近年来,分子生物学、免疫学等检测分析技术快速发展,相较于传统致病菌检测方法的繁琐耗时,这些方法灵敏度高、检测速度快、操作简单,因而备受关注。本文对近年来食源性致病菌检测新技术及应用进行综述,并对乳制品中食源性致病菌快速检测技术可能的发展趋势进行展望,以期为乳制品中食源性致病菌快速检测提供参考。     

多重PCR-膜芯片技术快速检测饲料中6种致病微生物

本实验基于多重PCR与膜芯片核酸杂交技术，旨在构建同时检测饲料及原料中6种致病微生物的检测方法，并对方法的特异性、检出限及适用性进行了验证。结果表明：该方法具有良好重复性、再现性和特异性，综合检出限为培养前1～5 CFU/mL（核酸样本为0.01 ng/μL），可实现对沙门氏菌、大肠埃希氏菌O157:H7、金黄色葡萄球菌、志贺氏菌、单核细胞增生李斯特氏菌、副溶血性弧菌等6种致病微生物的高通量检测，检测结果与标准方法一致。多重PCR-膜芯片技术可成为饲料及原料中微生物污染快速、高通量筛查新的技术手段。     

石河子地区动物性食品中单核细胞增生李斯特菌的检测

目的了解新疆石河子地区动物性食品中单核细胞增生李斯特氏菌(LM)污染状况。方法在石河子地区选取5个具有代表性动物性食品零售点,对最常食用的生鲜猪肉、牛肉、羊肉、鸡肉、冻鸡肉、冻虾和冻带鱼8类动物性食品进行随机采样,采用病原分离培养和PCR法对样品中的单核细胞增生李斯特氏菌进行检测。结果检测8类249份食品样品,细菌分离鉴定阳性样品12份,平均阳性率4.82%;PCR法检测阳性样品36份,平均阳性率为14.46%。结论石河子动物性食品中LM的污染比较普遍,尤以冻鸡肉和冻虾LM污染较重,新鲜猪肉、牛肉和羊肉LM污染程度较轻。     

2017年酒泉市部分地区市动物性食品喹诺酮类抗生素残留情况调查与分析

研究旨在初步了解并分析甘肃省酒泉市部分地区市动物性食品喹诺酮类抗生素残留情况,为相应的膳食安全评估提供基础数据。于2017年3—10月在酒泉市部分地区随机采集动物性食品共235份,应用超高效液相色谱-串联质谱法对被检样品中喹诺酮类抗生素残留进行检测与分析。结果表明:235份样品中有14份样品检测含有喹诺酮类抗生素残留,检出率5.96%,其中猪肉、鸡肉、鸡蛋、羊肉和牛肉的检出率分别为4.56%(2/43)、4.17%(1/24)、25.00%(5/20)、4.69%(6/128)和0.00%(0/20),且2份鸡蛋样品检测超标,超标率0.85%(2/235);此外,14份阳性样品中恩诺沙星的检出率最高,为64.28%(9/14)。说明酒泉市部分动物性食品存在喹诺酮类抗生素残留,对消费者健康造成一定的威胁,应引起相关部门的重视。     

Protection activity of a novel probiotic strain of Bacillus subtilis against Salmonella Enteritidis infection

The activity of 240 bacterial isolates screened from the gastrointestinal tracts of native chickens were evaluated for use as a potential probiotic in food animal production in order to protect against animal diseases and reduce pathogenic contamination of human food products. In observing the antagonistic activity of 117 bacilli isolates, 10 of these isolates exhibited higher growth inhibition of seven foodborne pathogens, including Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, and Vibrio cholerae. Beneficial probiotic criteria from these isolates - which included non-pathogenicity, acid and bile salt tolerance, hydrophobicity, and adhesion to intestinal epithelial cells - exhibited that one isolate of NC11 had the most potential as a probiotic. 16S rRNA gene sequencing showed that this NC11 isolate was Bacillus subtilis. This B. subtilis NC11 was sensitive to all antibiotics and was not cytotoxic to intestinal epithelial cells. Reduction of S. Enteritidis attachment to the surfaces of intestinal epithelial cells via action of a cultured medium from B. subtilis NC11 was observed by scanning electron microscopy. B. subtilis NC11 cells, as well as the bacterial cultured medium or the cultured medium adjusted to pH 7, significantly inhibited S. Enteritidis invasion (P<0.01) of intestinal epithelial cells. This study indicates that B. subtilis NC11 has characteristics of a potential probiotic, and exhibits strong inhibition activity against S. Enteritidis infection to intestinal epithelial cells.     

PCR技术在乳及乳制品致病菌检测中的应用

PCR技术是1985年诞生的一项DNA体外扩增技术,具有特异性强、敏感性高、操作简便、快速高效等特点,被广泛地应用于生物科学的各个领域。作者介绍了PCR技术的基本原理及其在几种致病菌如金黄色葡萄球菌、沙门氏菌、志贺氏菌、单核细胞增生李斯特氏杆菌及其他一些有害微生物在乳及乳制品检测中的应用。     

Public health and research perspectives on the microbial contamination of foods

Scientific advances in methodology and epidemiology have resulted in a renewed awareness of foodborne disease, and increased contact among nations of the world has stimulated rapid global distribution of foods as well as foodborne pathogens. New food vehicles are being identified for old, familiar pathogens, and new pathogens are being discovered. Current research in food microbiology has spurred development of rapid and specific methods to identify these pathogens and to assess their virulence. Organisms of recent interest, such as Bacillus, Yersinia, Campylobacter, Listeria, Sporothrix, Giardia, Cryptosporidium, and Anisakis, are the foci of new investigations, as are the more familiar foodborne pathogens, Salmonella, Shigella, Clostridium, Staphylococcus, Entamoeba and Ascaris. Some foodborne organisms, such as parasitic protozoa, serve as hosts for unique bacterial and viral symbionts but also might become infected with mammalian viruses. The remote possibility of the transmission of human immunodeficiency viruses in foodborne protozoa is discussed.     

不同来源乳酸菌的分离与鉴定

Six strains of Lactobacillus were isolated from traditional indigenous dairy products, piglet’s feces and chicken intestine, designated as LS, LT, LJ1, LJ2, LZ1 and LZ2， respectively. Identifications were done according to bacteria morphology, physiological and biochemical properties,16S rDNA sequence homology analysis, and their characteristics were researched. The results showed that LS, LT, LJ1 and LZ2 strains were Lactobacillus brevis, LJ2 strain was Enterococcus faecium, LZ1 strain was Lactobacillus acidophilus. All of the six strains had obvious bacteriostasis effect on Listeria monocytogenes, Salmonella typhimurium, Escherichia coli and Staphylococcus aureus.     

应用环介导等温扩增技术快速检测单核细胞增生李斯特菌的研究

目的建立环介导等温扩增技术快速检测单核细胞增生李斯特菌。方法根据单核细胞增生李斯特菌(LM)hlyA基因序列中的保守区域,采用在线引物设计软件Primer Explorer4.0进行设计,获得一套特异性的环介导等温扩增(LAMP)引物,对单核细胞增生李斯特菌hlyA基因进行LAMP扩增,并与常规PCR方法进行比较。结果建立的LAMP方法能成功扩增出梯形条带,LAMP检测单核细胞增生李斯特菌纯培养物和人工染菌的灵敏度为5.44×102cfu/mL,而对照PCR检测的灵敏度为5.44×104cfu/mL。对10株细菌进行LAMP扩增,仅单核细胞增生李斯特菌得到阳性结果。从DNA提取到报告结果,耗时仅1h。结论 LAMP检测单核细胞增生李斯特菌灵敏度高,特异性强,耗时短,方法简便,有望发展成为快速检测食品中单核细胞增生李斯特菌的有效手段。     

Foodborne zoonoses due to meat: a quantitative approach for a comparative risk assessment applied to pig slaughtering in Europe

Foodborne zoonoses have a major health impact in industrialised countries. New European food safety regulations were issued to apply risk analysis to the food chain. The severity of foodborne zoonoses and the exposure of humans to biological hazards transmitted by food must be assessed. For meat, inspection at the slaughterhouse is historically the main means of control to protect consumers. However, the levels of detection of biological hazards during meat inspection have not been established in quantitative terms yet. Pork is the most frequently consumed meat in Europe. The aim of this study was to provide elements for quantifying levels of risk for pork consumers and lack of detection by meat inspection. Information concerning hazard identification and characterisation was obtained by the compilation and statistical analysis of data from 440 literature references. The incidence and severity of human cases due to pork consumption in Europe were assessed in order to calculate risk scores. A ratio of non-control was calculated for each biological hazard identified as currently established in Europe, i.e. the incidence of human cases divided by the prevalence of hazards on pork. Salmonella enterica, Yersinia enterocolitica and Campylobacter spp. were characterised by high incidence rates. Listeria monocytogenes, Clostridium botulinum and Mycobacterium spp. showed the highest severity scores. The three main high risk hazards involved in foodborne infections, Y. enterocolitica, S. enterica and Campylobacter spp. are characterised by high non-control ratios and cannot be detected by macroscopic examination of carcasses. New means of hazard control are needed to complement the classical macroscopic examination.     

哈尔滨市鲜肉中单核细胞增生性李斯特菌的分离鉴定及耐药性分析

为了解哈尔滨市单核细胞增生性李斯特茵(Lm)的污染状况及耐药状况.在哈尔滨市市场随机采集158份鲜肉样品,采用显色培养基分离,API试剂条和PCR鉴定等方法对样品中的Lm进行分离鉴定,并通过Kirby-Barer法测定分离菌株对24种抗生素的耐药性.结果从鲜肉中共分离到Lm 23株,检出率为14.56%,其中鲜猪肉检出率最高,达20.00%(14/70);23株分离菌株中耐药菌株为22株,耐药率高达95.65%.这表明哈尔滨市鲜肉中存在一定程度的Lm污染,并且分离菌株存在较严重的耐药现象.应加强控制动物饲料亚治疗抗生素的使用并严格遵守休药期,防止耐药菌株产生进而控制食源性疾病的发生.     

Molecular characterization of Listeria monocytogenes and the significance for food hygiene

Research on the pathogen Listeria monocytogenes is a key issue both for the clinical and the food microbiologist owing to the unique pathway of infection and the exposure of humans via contaminated foods. Although, in Austria, the incidence of listeriosis is about 870-fold lower than the incidence for Salmonella infection, the food law manages both foodborne pathogens with a comparable stringency. The current risk management is based on the assumption that environmental L. monocytogenes isolates, from which the pool of "foodborne" isolates is recruited, are of similar pathogenicity compared to clinical and outbreak isolates. This verdict became doubted in the recent years. Characterization of L. monocytogenes by virulence gene sequencing, virulence studies in vivo and in vitro and by molecular typing was considerably stimulating the discussion on virulence variability in L. monocytogenes. This article provides insights in the value of epidemiological follow-up studies by presenting a typing study on 15 cases of listeriosis observed in a district hospital in Turkey. Furthermore results from typing L. monocytogenes either by virulence gene sequencing, mismatch amplification mutation assay or by pulsed field gel electrophoresis are discussed. The close interaction of molecular microbiology with food microbiology both in applied and basic science is currently creating a new discipline of molecular food microbiology. We are convinced that veterinary medicine will contribute to this exiting development in a fruitful way.