目的 采用三代单分子实时测序法(single molecule real time sequencing, SMRT)研究北京和内蒙古两地原料乳中的细菌群落组成及多样性,解析其携带污染菌的差异,为原料乳质量及风险评估提供基础数据。方法 收集北京和内蒙古两地春夏季和...目的 采用三代单分子实时测序法(single molecule real time sequencing, SMRT)研究北京和内蒙古两地原料乳中的细菌群落组成及多样性,解析其携带污染菌的差异,为原料乳质量及风险评估提供基础数据。方法 收集北京和内蒙古两地春夏季和秋冬季的原料乳样品20份,采用SMRT技术对其进行基于16S rDNA基因全长的测序和多样性分析。在此基础上,对其进行了微生物相关功能性预测。结果 不同产地与不同采样季节原料乳中细菌群落的结构组成和相对丰度存在差异,假单胞菌属、不动杆菌属与乳球菌属是大部分样品中相对丰度最高的细菌,其中脆弱假单胞菌的相对丰度与原料乳冷链运输时间正相关。功能预测揭示了原料乳脂肪质量可能具有地区差异性,维生素与氨基酸质量可能具有季节差异性。结论 两产地原料乳菌群分析结果提示了原料乳潜在的食品安全风险,并且除致病菌风险之外耐药菌及耐药基因传播的风险同样不容忽视;此外,乳球菌属细菌具有开发作为益生菌的潜力。本研究结果为原料乳的质量安全监测评估和功能菌种挖掘提供了参考依据。展开更多
Introduction:Raw milk is the basic raw material of dairy products.Bacillus cereus(B.cereus)is a typical conditional pathogenic bacteria and cold-phagocytic spoilage bacteria in raw milk.Materials and Methods:In this s...Introduction:Raw milk is the basic raw material of dairy products.Bacillus cereus(B.cereus)is a typical conditional pathogenic bacteria and cold-phagocytic spoilage bacteria in raw milk.Materials and Methods:In this study,a quantitative polymerase chain reaction(qPCR)method for detecting B.cereus in raw milk was established.The specificity of the method was verified by using other Bacillus bacteria and pathogenic bacteria;the sensitivity of the method was evaluated by preparing recombinant plasmids and simulated contaminated samples;and the applicability of the method was verified using pure spore DNA.The actual sample detection was completed by using the established qPCR method.Results:The qPCR established in this study can specifically detect B.cereus in raw milk.The limit of detection of the method was as low as 200 CFU/mL,the limit of quantification ranged from 2×10^(2)to 2×10^(8)CFU/mL,and the amplification efficiency of qPCR was 96.6%.Conclusions:The method established in this study can distinguish B.cereus from other Bacillus bacteria,and spore DNA can be used as the detection object.This method has the advantages of strong specificity,high sensitivity,wide application range,and short detection time,which isexpectedtobeapplied in thedairy industry.展开更多
文摘目的 了解我国粮食加工品和肉制品中克罗诺杆菌(Cronobacter spp.)的污染情况及致病性。方法对我国8个省份的226份粮食加工品和肉制品的克罗诺杆菌污染情况进行检测,对分离菌株进行种间鉴定,并针对阪崎克罗诺杆菌进行脉冲场凝胶电泳(pulsed field gel electrophoresis, PFGE)分型及生物膜形成能力研究。结果 粮食加工品和肉制品中克罗诺杆菌的检出率分别为21.92%和12.50%。种间鉴定显示,115株分离菌株中有94株阪崎克罗诺杆菌。PFGE和结晶紫染色结果表明,94株阪崎克罗诺杆菌可被分为49个型别,均在36~60 h内达到最大菌膜生产量。结论 上述8个省份粮食加工品和肉制品中存在克罗诺杆菌污染,其中阪崎克罗诺杆菌有多种PFGE带型,且均具有生物膜形成能力,本研究可为食品安全风险评估及标准制定提供基础数据。
基金supported by the National Key Research and Development Program of China (2018YFC1604201 and 2018YFC1603800).
文摘Introduction:Raw milk is the basic raw material of dairy products.Bacillus cereus(B.cereus)is a typical conditional pathogenic bacteria and cold-phagocytic spoilage bacteria in raw milk.Materials and Methods:In this study,a quantitative polymerase chain reaction(qPCR)method for detecting B.cereus in raw milk was established.The specificity of the method was verified by using other Bacillus bacteria and pathogenic bacteria;the sensitivity of the method was evaluated by preparing recombinant plasmids and simulated contaminated samples;and the applicability of the method was verified using pure spore DNA.The actual sample detection was completed by using the established qPCR method.Results:The qPCR established in this study can specifically detect B.cereus in raw milk.The limit of detection of the method was as low as 200 CFU/mL,the limit of quantification ranged from 2×10^(2)to 2×10^(8)CFU/mL,and the amplification efficiency of qPCR was 96.6%.Conclusions:The method established in this study can distinguish B.cereus from other Bacillus bacteria,and spore DNA can be used as the detection object.This method has the advantages of strong specificity,high sensitivity,wide application range,and short detection time,which isexpectedtobeapplied in thedairy industry.
