2012年张家港口岸进境冷冻猪肉制品中单核细胞增生李斯特氏菌污染调查简

目的 了解进境冷冻猪肉制品单增李斯特菌污染状况,建立流行病学监测网,以便制定良好的预防控制措施,更有效地预防和控制由该菌引起的食源性疾病和疫情的发生.方法 mini VIDAS快速筛选、显色平板分离、API Listeria鉴定结合国标法进行单增李斯特菌检测.结果 2012年共检测冷冻猪肉制品171批,检出单增李斯特菌14株,阳性率为8.19％（14/171）.结论 单增李斯特菌污染较为严重,应加强对冷藏生畜、肉类食品的卫生管理.     

湖州市食品中单增李斯特菌的污染状况调查

目的:了解湖州市食品中单增李斯特菌的污染状况。方法:按国标方法,采用进口显色培养基,对食品进行单增李斯特菌的分离、生化鉴定。结果:281份样品中共检出22株,污染率为7.83%。其中冷冻/藏鸡肉中污染率最高,为25.00%。结论:湖州市食品中单增李斯特菌的污染比较严重,应加强对生肉制品等的监督管理,以防食源性疾病的发生。     

套式PCR快速检测单增李斯特氏菌

根据GenBank数据库的单增李斯特氏菌iap基因设计两对引物,建立了套式PCR快速检测单增李斯特氏菌的方法。两对引物分别扩增出约1500bp和500bp片段,与预期大小一致。对菌液、模拟样品的检测表明,本方法能有效地克服食品基质、培养基成分和杂菌对PCR检验的干扰作用。套式PCR方法具有很好的特异性;灵敏性实验检测极限为101CFU／ml;人工污染猪肉检测极限为103CFU／ml;可在7h内完成检测,很适宜于进出口食品中单增李斯特氏菌的快速检测。     

食品中菌落总数与金黄色葡萄球菌定量检测能力验证结果与分析

目的为了提高实验室食品安全检测能力及水平,保证检测结果持续有效,控制管理实验室检测质量。方法依据国家标准GB 4789.2-2010和GB 4789.10-2010,采用两种定量方法,两种增菌液和分离培养基,对代码为A398菌落总数和B873金黄色葡萄球菌定量样品进行检测。结果菌落总数（代码A398）结果为2.3×104CFU/ml;金黄色葡萄球菌定量（代码B873）结果为平板计数法630 CFU/ml,MPN法为1 100 MPN/ml。两份样品测试结果由中国检验检疫科学研究院综合检测中心给出评价,菌落总数Z分值为0.00;金黄色葡萄球菌定量Z分值为0.36,取得满意结果。结论金黄色葡萄球菌显色培养基比Baid-Parker平板更适合金黄色葡萄球菌的定量检测。     

单增李斯特菌PCR-ELISA快速检测技术研究

目的建立快速检测单增李斯特菌的PCR-ELISA方法,将其应用于人工污染的食物样品检测。方法根据GenBank数据库资料,应用分子生物学软件DNAMAN6.0和Primer Premier5.0,以单增李斯特菌的致病基因hlyA为基础,选用PCR引物,应用地高辛标记试剂盒,获得单增李斯特菌特异的地高辛标记片段。根据PCR目的片段序列,设计特异性捕获探针,建立了单增李斯特菌PCR-ELISA快速检测方法。应用该方法对不同血清型的单增李斯特菌食品分离株进行了检测,并将PCR方法与PCR-ELISA方法对人工污染单增李斯特菌的牛奶样品的检测敏感性进行了比较。结果应用单增李斯特菌特异的PCR-ELISA方法完成检测约需6h。该方法对单增李斯特菌分离株检测的结果,与国家食源性疾病检测网的鉴定结果100%符合。经过12h的增菌培养,PCR-ELISA方法最低可从25ml样品中检出1CFU,检测敏感性为传统PCR方法的10～100倍。结论建立了单增李斯特菌PCR-ELISA快速检测方法。该方法敏感性高、特异性强、可靠性好,对于提高食源性疾病预警、预测能力,增强检测的时效性和准确性,具有推广应用价值。     

两种沙门氏菌定量计数方法的比较

目的为了准确计数生鲜肉中的沙门氏菌的数量,为微生物危险性评估提供精确的数据支持,探索一种实用性、准确性和选择性的沙门氏菌计数方法。方法将污染不同数量沙门氏菌的样品分别稀释,同时用平板计数法和MPN法分别计数,比对两方法的准确度、灵敏度和可操作性。平板计数选用CHROMagar显色培养基平板和XLD琼脂平板作分离平板,挑取可疑菌落经鉴定后,计算沙门氏菌数。MPN法选用TTB、MM和SC增菌液分别于(36±1)℃、(42±1)℃增菌后,接种CHROMaagar显色培养基平板和XLD琼脂平板,挑取可疑菌落鉴定后查MPN表。结果样品中污染沙门氏菌量在1~500cfu/g时,平板计数法不能将沙门氏菌很好地区分;MPN法采用SC增菌液(42±1)℃培养效果最好,检出限10cfu/g,检测值和理论值(在500cfu/g)的符合率为92.0%。结论MPN法无论从可操作性或是检出的灵敏度都要优于平板计数法。     

食品中沙门菌的检测

目的：检测超市奶类和肉类制品中沙门菌的污染情况,初步评价检测食品中沙门菌的检测方法。方法：样品经增菌后,用科玛嘉显色培养基培养、ELISA法、国标法对超市的奶类和肉类制品中的沙门菌进行平行检测,并对其灵敏性和特异性、符合率进行比较分析。结果：检测320份奶类制品和肉制品,科玛嘉显色培养基培养、ELISA法、国标法阳性样品数分别为23份、26份、20份,其阳性率分别为7.2%、8.1%、6.3%。科玛嘉显色培养基培养的敏感性和特异性分别为100%、99%,与国标法的符合率达99.1%。ELISA法的敏感性和特异性分别为100%、98%,与国标法符合率98.1%。ELISA法与科玛嘉显色培养基培养的符合率为99.1%。157份奶类制品,科玛嘉显色培养基培养、ELISA法、国标法检测阳性样品数分别为6、6及5份,阳性率分别为3.8%、3.8%和3.2%,有2份检测结果不一致。163份肉类制品,阳性样品分别为17、20、15份,阳性率分别为10.4%、12.3%和9.2%,有5份肉食品检测结果不一致。结论：科玛嘉显色培养基培养、ELISA法和国标法对超市的奶类和肉类制品中的沙门菌进行平行检测,符合率高。利用科玛嘉显色培养基培养、ELISA法,可以快速、方便地对食品中沙门菌的污染进行批量初筛,科玛嘉显色培养基鉴别培养特异性好,更适合食品沙门菌的分离与初筛检测。     

食品中产单核细胞增生李斯特菌污染状况的分析

[目的]了解马鞍山市7类食品中单增李斯特菌污染状况,并评价不同方法的检测效果,为食品中单增李斯特菌定量风险评估提供科学依据. [方法]依据国标GB4789.30-2003和国家食源性疾病监测网2007年年度工作手册进行,同时用EB增菌法、LB增菌法和Fraser肉汤培养法对食品样品进行单增李斯特菌分离鉴定并进行比较. [结果]7类482份食品样品,检出单增李斯特菌(L.m)56株,检出率为11.62%;在288份生肉和水产品中检出28株产H2S李斯特菌,阳性率为9.72%. [结论]在7类食品中除冰淇淋外,均不同程度受到L.m污染,尤以速冻面米食品污染严重,其次为熟肉制品、生畜禽肉和水产品.LB增菌法明显优于EB增菌法,Fraser肉汤培养法和LB增菌法检出率相等,而后者操作更方便.     

Veriflow DNA签名捕获技术在检测食品中单增李斯特菌的应用

【目的】建立快速检测食品中单增李斯特菌的实验方法。【方法】与国家标准方法对比研究Veriflow方法检测单增李斯特菌的效能,对3种食品样品和4种环境表面样品进行单增李斯特菌的定性检测,以建立和验证快速检测食品中单增李斯特菌的实验方法。【结果】Veriflow方法的检测结果与国标方法的结果差异无统计学意义(P0.05)。Veriflow方法的特异性验证结果显示该法对单增李斯特菌检测的包容性和特异性均为100%。Veriflow方法的检测时间只需26 h,短于国家标准的检测时间(6 d),检测效率明显提高。【结论】Veriflow是一种准确、特异性强并且操作简单的单增李斯特菌快速检测方法,具有良好的推广前景。     

新型的LMX肉汤对单增李斯特菌的检测效果评价

目的评价一种新型的快速单增李斯特菌(LMX)肉汤对单增李斯特菌的增菌效果。方法对目标菌株的灵敏度、生长率、选择性及生化反应等几个方面进行测试,根据测试结果来判断新型培养基的增菌效果。结果新型培养基与国标推荐方法中使用的培养基的增菌效果相当。结论此液体培养基可以作为单增李斯特菌的快速检测用增菌液。     

显色培养基在单核细胞增生李斯特菌快速检测中的应用研究

目的:研究显色培养基对单核细胞增生李斯特菌的检测效果,探讨建立新型快速检测方法。方法:检测按国标GB4789-33程序进行。结果:人工污染样品和实际样品检测中,显色培养基CHROM agar L isteria和HKL isteria与传统平板OXA和MMA可以达到相同的检测限和灵敏度,且具有更高的特异性。结论:用显色培养基检测单核细胞增生李斯特菌是一种新途径,可大大提高检测效率。     

黑龙江省食品中单核细胞增生李斯特氏菌污染监测

目的为掌握黑龙江省食品中单核细胞增生李斯特氏菌污染状况，构建食品中单核细胞增生李斯特氏菌污染数据库。方法在黑龙江省选取6个具有代表性城市建立监测哨点，定期对6类食品进行采样，检验采用增菌液（LB1、LB2）增菌后，用科玛嘉显色培养基分离，再做相应的生化及API Listeria快速反应板鉴定。结果检测6类760份食品样品，检出单核细胞增生李斯特氏菌（L．m）43株，检出率为5．66％。结论黑龙江省食品均不同程度受到L．m的污染，尤以生畜禽肉、非定型包装熟肉污染严重，淡水产品次之，生食蔬菜少见。     

Bacteriological quality of raw milk used for production of a Brazilian farmstead raw milk cheese

The objective of this study was to evaluate the bacteriological quality of raw cow's milk utilized for the production of Traditional Minas Serro cheese, a Brazilian farmstead raw milk cheese. Raw milk samples were collected from six farmstead cheese operations manufacturing raw milk cheese from cow's milk. Coliform count (CC) and Escherichia coli counts were determined using Petrifilm? EC plates, and Staphylococcus aureus counts were determined using Petrifilm? Staph Express count plates. The standard plate count (SPC) was determined using plate count agar. The somatic cell count (SCC) was determined with a DeLaval cell counter. The detection of Listeria monocytogenes was based in the ISO 11290-1 protocol. A total of 165 samples were analyzed, and the SPC was 1.85-7.88 log CFU/mL. Coliform were detected in 140 (84.8%) of the 165 samples, with counts of 1-6.39 log CFU/mL. E. coli was detected in 17 (10.3%) samples, with counts of 1-2.18 log CFU/mL. The SCC in raw milk was 10,000-1,390,000 cells per mL, with mean and geometric mean values of 247,000 and 162,181, respectively. The SCC did not differ significantly between the seasons (p>0.05), but differed between different farms (p<0.05). None of the 155 samples were positive for the presence of Listeria monocytogenes. S. aureus was isolated in 145 (94.1%) of the 154 samples, and the count was 1.47-5.03 log CFU/mL. The median of SPC, CC, and S. aureus counts differed significantly between seasons and between farms (p<0.05). Our results indicate that raw milk for production of farmstead raw milk cheese has a low incidence of L. monocytogenes and a high incidence of S. aureus, and suggest that measurements (such as SCC or SPC) may not serve as a predictor of other bacterial (including pathogenic) presence.     

全自动微生物磁珠分选系统检测单核细胞增生李斯特菌效果研究

目的:研究全自动微生物磁珠分选系统对食品中单增李斯特氏菌的检测效果。方法:取400份自然样品,用磁珠分选系统和国标法对样品进行对比检测。结果:全自动微生物磁珠分选系统相较国标法对自然样品中单核细胞增生李斯特氏菌阳性检出率有一定程度提高。结论:全自动微生物磁珠分选系统简单易用,标准化程度高,可以和国标检测方法相结合以提高单增李斯特氏菌的检出率。     

2016-2018年湖南省含乳冷冻饮品生产加工过程肠杆菌科和单核细胞增生李斯特菌监测

目的 了解含乳冷冻饮品生产加工过程中肠杆菌科和单核细胞增生李斯特菌(简称单增李斯特菌)的分布,分析其污染的来源. 方法 对湖南省4家含乳冷冻饮品生产企业生产加工过程各个环节的样品进行监测,采用国家标准检测方法对肠杆菌科和单增李斯特菌进行检验,利用脉冲场凝胶电泳(pulse field gel electrophores...     

一项关于食品中空肠弯曲菌计数方法的研究简

目的 为了了解食品中空肠弯曲菌的数量,探寻一种实用的空肠弯曲菌计数方法.方法 通过不同浓度的染菌实验,对平板计数法、MPN法和Simplate方法进行比较分析.结果 当染菌量在10 CFU/g（mL）时,MPN法中至少有1管出现了阳性,simplate也可以检出且与设定值接近.因此这两种方法的检测限均为≥10 CFU/g（mL）.平板计数法的检测限应为≥30 CFU/g（mL）,在此范围内得到的结果与设定值相差0.9 ～2.4倍,小于10倍.结论 事实上,实验室可以选用不同的方法来评价食品中空肠弯曲菌的污染情况.如果检疫过程中要求结果准确,我们建议使用MPN和Simplate方法来计数加工过的食品.对于猪肉和家禽这类高污染的畜产品,选用平板计数法计数则更便捷.     

Microbiological profile of raw Nile water

With the increase of population on the Nile banks, a remarkable increase in industrial, agricultural, human activities, and recreational activities have also occurred. The effluents of such activities are discharged directly into the Nile or through some agricultural drains which finally discharge their wastes into the Nile. Thus, the microbiological monitoring is one of the main objectives to protect the river Nile. This study was conducted to determine the microbiological profile of river Nile at Cairo segment. Eight sites were chosen along the distance (60 Km) from El-Shobak to El-Kanater and tested for two successive years (summer 1994-spring 1996). To achieve this goal, microbiological parameters (total bacterial counts at both 22 degrees C and 37 degrees C, total coliforms, faecal coliforms, faecal streptococci, total yeasts, Candida albicans, Aeromonas hydrophila, salmonellae, total staphylococci, total vibrios and Listeria group) were evaluated. The results showed that the count of the previous parameters ranged between 1.0x10(3)-7.8x10(5) CFU/ml, 5.0x10(2)-6.4x10(5) CFU/ml, 4.9x10-1.6x10(4) MPN/100 ml, 2.0-5.2x0(3) MPN/100 ml, 2.0x10-1.4x10(3) MPN/100 ml, 1.7x10(3)-2.6x10(5) CFU/100 ml, 1.5x10(2)-1.7x10(5) CFU/100 ml, 1.0x10(3)-2.4x10(5) CFU/100 ml, 1.3x10(2)-5.1x10(3) CFU/100 ml, 1.0x10(2)-3.3x10(3) CFU/100 ml, 1.0x10(2)-3.8x10(4) CFU/100 ml and 1.0x10(2)-1.4x10(5) CFU/100 ml, respectively. The total bacterial counts and bacterial indicators (total coliforms, faecal coliforms and faecal streptococci) were detected in all samples during the period of study, and the count increased in samples collected during summer than other seasons. Also total yeasts, A. hydrophila and total staphylococci were detected in all samples with differences in count between the sites. In contrast, other microbial parameters, Candida albicans, salmonellae, total vibrios and Listeria group were not detected in some samples at some sites. According to our results it can be concluded that the river Nile is categorized as an intermediately polluted river.     

Antimicrobial effects of garlic,clove and red hot chilli on Listeria monocytogenes in broth model systems and soft cheese

Antimicrobial activity of 1% (w/v) fresh garlic, ground clove and red dried chilli on Listeria monocytogenes was tested in broth systems at 37 degrees C and at 4 degrees C for 7 h. The initial cell concentration in the broth systems was between 2 x 10(6) and 4 x 10(6) CFU/ml. At 37 degrees C, growth to viable numbers of 3 x 10(8) CFU/ml in 7 h was measured. Clove had bacteriocidal activity and reduced the count to 1 CFU/ml. Garlic displayed bacteriostatic properties, and a count of 4 x 10(6) CFU/ml was maintained. Red chilli displayed an inhibitory effect and resulted in 50% lower counts than the control. L. monocytogenes had a slow growth rate at 4 degrees C and increased from an initial value of 3 x 10(6) to 5 x 10(6) CFU/ml during 7 h. The addition of garlic resulted in 3 x 10(6) CFU/ml, and clove reduced the viable cell concentration to 1 x 10(3) CFU/ml after 7 h. Two batches of soft cheese were produced in the laboratory using milk that was supplemented with L. monocytogenes. The final cheese containing L. monocytogenes with about 1 x 10(5) CFU/g. Half of each cheese batch was supplemented with either 1% garlic or 1% clove, whereby the other half served as a control. After 7 or 11 days incubation at 4 degrees C, the cheese was incubated at abuse temperature of 25 degrees C for 7 or 3 days, respectively. No antimicrobial effects of 1% (w/w) fresh garlic or clove powder on L. monocytogenes were observed in cheese after 1 or 2 weeks at the lower or higher temperature.