餐饮具表面的大肠杆菌和金黄色葡萄球菌活性研究

目的研究温度、湿度及餐饮具材质对餐饮具表面大肠杆菌和金黄色葡萄球菌活性的影响。方法分别在同一湿度50%、不同温度(25℃、37℃和60℃)下及同一温度25℃、不同湿度(20%、50%)条件下接种大肠杆菌和金黄色葡萄球菌到陶瓷餐饮具表面,在10、30、60和120 min后检测两种细菌的存活数量;在25℃、湿度50%的条件下分别接种两种细菌到陶瓷、木质、不锈钢和铜合金的餐饮具上,在10、30 min后检测两种细菌的存活数量。结果在同一湿度(50%),25℃时,两种细菌活性均较好;37℃时,存活的大肠杆菌数量比金黄色葡萄球菌低10~2 CFU/m L;60℃时,大肠杆菌10 min后失活,金黄色葡萄球菌60 min后失活。在25℃,湿度20%时,存活的大肠杆菌数量10 min后下降103 CFU/m L,120 min后失活;湿度50%时,存活的大肠杆菌数量120 min后仅下降10~2 CFU/m L。而金黄色葡萄球菌在两种湿度条件下,存活的细菌数量120 min后仅下降10 CFU/m L。在25℃、湿度50%的条件下接种10 min后,铜合金餐饮具上的两种细菌比其他材质的低10~2CFU/m L,30 min后,铜合金餐饮具上的两种细菌均失活。结论大肠杆菌对高温和干燥的耐受性比金黄色葡萄球菌弱。陶瓷、木质和不锈钢餐饮具对大肠杆菌和金黄色葡萄球菌均无抑菌性,而铜合金餐饮具对两种细菌均有抑菌性。     

ATP生物发光技术快速检测牛乳体细胞数

探索利用ATP生物发光技术快速检测牛乳体细胞数的可行性.利用ATP生物发光技术测定牛乳体细胞ATP浓度,根据体细胞中ATP的浓度与体细胞数成正比的原理,推算出牛乳中的体细胞数,并与显微镜计数法对比,分析两种方法之间的相关性.结果表明:ATP生物发光技术的检测结果与显微镜计数法有很好的相关性,是一种快速、简便的检测牛乳体细胞的方法.     

金黄色葡萄球菌两种检测方法的比较研究

目的比较Baird-Parker平板计数法和3M Petrifilm~(TM)测试片法检测金黄色葡萄球菌的优缺点。方法采用GB 4789.10-2010《食品微生物学检验金黄色葡萄球菌检验》、SN/T 1895-2007《食品中金黄色葡萄球菌的快速计数法Petrifilm~(TM)测试片法》检测金黄色葡萄球菌菌悬液,并对结果进行分析比较。结果在高浓度菌液(102 CFU/mL)时,国标法和测试片法检测金黄色葡萄球菌有显著差异,测试片法计数较困难,国标法检测结果值更准确,但测试片法在简便性、检测时间等方面都优于Baird-Parker法。结论对不同样品进行检测时应注意根据实际金黄色葡萄球菌污染程度选择合适的方法。     

手持式ATP荧光检测仪性能评价

目的建立一种评价手持式ATP荧光检测仪的方法 ,并分析目前市场上手持式ATP荧光检测仪的技术现状。方法对目前市场上常见的10家公司的手持式ATP荧光检测仪的主要性能指标,包括线性、重复性、检出限及衰减率等进行检测,并对检测结果进行总结、分析。结果 10家公司产品的检测能力存在差异。线性范围和检出限存在数量级上的差异,精密度为7.3%～36.8%,衰减率为4.3%～81.5%,最后线性、重复性、检出限及衰减率等各项性能指标均达到要求的产品只有3家。结论为了使手持式ATP荧光检测仪满足不同行业对卫生质量的要求,应用于更多的领域,该产品的技术水平有待进一步提高。     

ATP荧光仪:快速解决清洁度检测——访上海美全生物科技有限公司执行副总经理彭志刚

20世纪60年代,美国国家航空航天局研发了以ATP生物发光检测技术为基础的探测器,旨在探寻外太空中的生命存在。此后,随着技术的进步,ATP生物发光法被广泛应用于各个领域。20世纪80年代,荷兰Lumac公司率先推出用于快速检测细菌污染状况的ATP荧光检测仪,如今已有多种用于检测不同项目的ATP荧光检测仪投放市场。为了进一步了解ATP荧光检测方法与设备的相关情况,本刊记者近日采访了上海美全生物科技有限公司执行副总经理彭志刚先生。     

CTAB提取ATP的生物荧光法快速检测细菌总数准确性研究

为降低ATP生物荧光法检测费用,本研究采用十六烷基三甲基溴化铵(CTAB)为细菌细胞ATP的提取剂,β-环糊精为中和剂,优化不同食品体系中细菌ATP的提取方法,同时检验CTAB提取ATP的生物荧光法快速检测细菌总数的准确性。结果表明:大肠杆菌、金黄色葡萄球菌、乳酸菌和枯草芽孢杆菌细胞采用CTAB提取出的细菌ATP的发光强度与细菌总数的线性相关性良好,相关系数均在0.92以上。对代表性的果汁、面、肉和奶制品经CTAB处理提取出细菌ATP后,对于细菌总数在103~107 CFU/mL的产品,根据ATP的荧光强度,能准确的判断出细菌总数,且生物荧光法与平板计数法两者检测结果的相关系数达到0.9895。但在原料肉的测定时,提取出的ATP的荧光强度与其细菌总数之间的相关性较差,为提高检测准确性,需要预先采用相关去除体细胞ATP干扰的配套试剂进行处理。     

基于ATP再生体系快速检测乳品中微生物

基于焦磷酸（pyrophosphoric acid,PPi）再生三磷酸腺苷（adenosine triphosphate,ATP）建立乳品中微生物快速检测方法。通过单因素试验优化PPi再生ATP反应条件,并考察方法的灵敏度、准确度、精密度和稳定性。结果表明,PPi再生ATP最佳反应条件为腺苷酰硫酸（adenosine phosphosulfate,APS）浓度10 μmol/L,ATP硫酸化酶（ATP sulfurylase,ATPS）活力0.15 U/mL、反应pH7.8。在最佳的ATP再生条件下偶联生物发光法,对ATP标准品、大肠杆菌、铜绿假单胞菌的检测限分别为10－17mol/mL、102CFU/mL和102CFU/mL。工作曲线在102～107CFU/mL范围内线性关系良好,对乳品基质的回收率为81.33%～97.78%,变异系数为14.24%～22.17%,与国标平板计数法对比显示两种方法检测结果相关性良好,相关系数为0.96。本方法快速、简单、灵敏、稳定,适用于乳品中微生物快速监测。     

仪器法快速检测鲜乳微生物的可靠性研究

本文通过乳制品微生物活性快速检测仪对鲜乳中微生物酶活性的测定,快速检测鲜乳中微生物数量的变化,判定鲜乳品质的优劣。试验结果表明:仪器法可以在30min内完成一个鲜乳样品的微生物含量的检测。利用鲜乳微生物快速检测仪和国标平板菌落计数法分别检测大肠杆菌、蜡样芽胞杆菌、变形杆菌、灰绿曲霉、黑曲霉、球拟酵母菌、金黄色葡萄球菌、伤寒沙门氏菌和志贺氏菌等主要危害鲜乳品质的菌落数量,两种方法的测定结果相关系数均在0.98以上,这表明两种方法间有很好的线性相关性,同样用两种方法监测鲜乳贮藏过程中的微生物活动情况,其检测结果 R2=0.991,属于显著相关。     

ATP生物发光法快速检测电子烟雾化液菌落总数

利用三磷酸腺苷(ATP)生物发光法建立快速检测电子烟雾化液微生物菌落总数的方法并进行优化,与国家标准微生物检测方法进行对比分析。结果表明:(1)ATP荧光检测仪的最优检测温度为25℃,反应时间为30s,ATP检出限为2.36×10~(-12) mol/L,RSD为3.5%~8.2%,加标回收率为97%~108%;(2)滤膜过滤富集检测可实现低活菌数样品的检测,混合纤维素酯滤膜的富集检测效果优于聚碳酸酯滤膜和醋酸纤维滤膜,富集后检测ATP生物荧光的相对光度值与富集前活菌总数具有良好的对数线性相关关系(r~20.96);(3)采用ATP检测方法估算的活菌总数结果与平板计数检测结果没有显著性差异(P0.05),对电子烟雾化液的卫生情况评价结果一致。ATP生物发光检测方法可快速计算电子烟雾化液菌落总数,对于电子烟安全卫生风险评估具有建设意义。     

速冻面米制品中金黄色葡萄球菌和肠毒素A基因三重PMA-qPCR快检方法的建立

为建立准确定量速冻面米制品中金黄色葡萄球菌活菌,筛查肠毒素sea基因并指示PCR反应假阴性的三重PMA-qPCR检测方法。针对金黄色葡萄球菌特异靶基因RpiR和肠毒素基因sea序列保守区,设计引物、探针和构建扩增内标,优化建立三重qPCR检测体系,建立PMA食品前处理方法去除死菌DNA,构建纯培养物和速冻面米制品中污染金黄色葡萄球菌的定量标准曲线,应用三重PMA-qPCR方法检测人工污染金黄色葡萄球菌的速冻面米制品。采用GB4789.10-2016中规定的选择平板计数法,评价三重PMA-qPCR方法的检测性能。结果表明,三重PMA-qPCR检测体系扩增效率高,特异性好。当食品中金黄色葡萄球菌污染量大于10~3CFU/g时,靶基因RpiR可获得有效扩增,污染量在10~3～10~7CFU/g之间时,扩增曲线线性良好(R~2=0.994),PMA-qPCR定量结果与平板计数结果一致性较好。当sea阳性菌株污染量大于10~3CFU/g时,应用PMA-qPCR方法可有效评估食品污染肠毒素A的风险。综上所述,本研究建立的三重PMA-qPCR检测方法操作简便,可快速定量检测速冻面米制品中金黄色葡萄球菌,评估食品污染肠毒素A的风险。     

螺旋平板法在菌悬液计数及食品和化妆品菌落总数检测中的应用

应用螺旋平板法和国标方法分别对金黄色葡萄球菌、沙门氏菌、大肠杆菌的培养菌悬液以及食品、化妆品样品161份进行菌落总数检测,国标法培养48h后进行手工计数,螺旋平板法自动接种培养48h后进行仪器自动计数,将两种方法结果进行比较,结果无显著性差异(P＞0.05)。因此螺旋平板法适用于菌悬液计数及食品和化妆品菌落总数的测定。     

Study on rapid quantitative detection of total bacterial counts by the ATP‐bioluminescence and application in probiotic products

The objective of this study was to develop a rapid quantitative detection method by triphosphate (ATP)‐bioluminescence and determine the feasibility to assay total bacterial counts (TBC) in probiotic products. A useful pretreatment technique to eliminate the interference to the ATP‐bioluminescence method was developed, resulting in a 10–100‐fold improvement in the rapid quantitative detection method by ATP‐bioluminescence. The TBC obtained by the ATP‐bioluminescence rapid detection method was tested against the direct microscopic count method or the plate count method and validated on three ATP Assay Systems. The results generated by the ATP methods and the plate count method were comparable to each other when the interference due to non‐microbial cell ATP and matter such as pigment were removed. This study reports the optimisation of an ATP‐bioluminescence assay using a pretreatment technique to eliminate interference in order to quickly determine the viable counts of bacteria in solid and liquid probiotic products.     

Microbial Assessment in School Foodservices and Recommendations for Food Safety Improvement

ABSTRACT:  This study evaluated microbial food safety in school foodservices. Five school foodservices were randomly selected, and samples from water, cooking utensils, tableware, foodservice surroundings, and linen were collected in summer and winter ( N = 420). Tap and drinking water samples were collected, samples of food contact surfaces were collected by swab-kit, and samples for foodservice workers' hands and gloves were prepared by glove juice method. Aerobic plate count (APC) and coliform bacterial populations were enumerated on plate count agar (PCA) and desoxycholate lactose agar, respectively. The presence of Escherichia coli , Salmonella , Listeria monocytogenes , and Staphylococcus aureus was also examined by biochemical identification tests. In addition, PCA agar for APCs and Baird-Parker agar for S . aureus were used to enumerate airborne microorganisms. Higher APCs (< 0 to 5.1 log CFU/mL) than acceptable level were generally observed in water samples, while low coliform counts were found in the samples. High APCs were enumerated in cooking utensils, foodservice workers, tableware, and foodservice surroundings, and coliforms were also found in the samples for both seasons. The presence of Salmonella was found from only 10% of plastic glove samples (summer), and the presence of L . monocytogenes was not observed in all samples. S . aureus was detected in some of water, cooking utensils, tableware, employees, and foodservice surroundings, and E . coli was observed in cooking utensils (10% to 20%; summer). No obvious airborne bacteria were detected. These results showed that sanitation practice in school foodservices should be improved, and the results may be useful in microbial assessment of school foodservices.     

Improved bioluminescent assay of somatic cell counts in raw milk

Somatic cell count (SCC) in milk is considered to be a valuable indicator of cow mastitis. For assessment of SCC in milk, the bioluminescent assay based on determination of ATP from somatic cells ([ATPsom]) in milk was proposed earlier. However, this assay is still not widely used in practice owing to lower reliability compared with conventional methods such as direct microscopy and flow cytometry. We revised the bioluminescent SCC assay and developed a simple protocol based on determination of the total non-bacterial ATP concentration in milk. It was shown that the novel ATP-releasing agent Neonol-10 (oxy-ethylated iso-nonyl phenol) has superior performance providing 100% lysis of somatic cells while not disrupting bacterial cells of milk at a concentration of 1.5% w/w. There was high correlation (R2=0.99) between measured bioluminescence and SCC as measured by direct microscopy. The observed detection limit of the bioluminescent milk SCC assay was as low as 900 cell/ml, time of analysis was 2-3 min per sample. The proposed method has high potential for on-site mastitis diagnostics.     

多种不同方法对微生物能力验证样品测试结果的比较及分析

目的在检测实验室能力验证样品时,通过多种方法进行比较,提高检测能力和结果准确性。方法菌落总数依据国标方法,在相同条件下由不同操作人员重复测定共10次,通过测量结果的不确定度的评定确定置信区间。大肠菌群通过3种方法计数,用大肠杆菌/大肠菌群测试片对大肠埃希氏菌进行快速定性判定。金黄色葡萄球菌通过不同培养基、涂布量、接种方法的7种不同组合方法进行检测。结果本次能力验证结果报告菌落总数结果为23000 CFU/mL、大肠菌群结果为10000 CFU/mL、金黄色葡萄球菌结果为12000 CFU/mL、大肠埃希氏菌检出。4项测试结果均为满意。结论通过多种方法同步进行,能有效提高检测能力和结果准确性。     

生物发光快速测定生乳菌落总数的方法

为消除利用ATP生物发光法测定生乳菌落总数时非细菌ATP对测定结果的干扰,建立了一种样品前处理方法。利用ATP生物发光法对经过前处理的生乳样品进行检测,结果表明,生乳菌落总数对数值与生乳细菌ATP发光对数值呈现较好的线性关系(R2=0.982),相关程度为显著相关(P<0.01),说明该前处理方法能够有效排除非细菌ATP的干扰,有利于提高ATP生物发光法定量测定生乳菌落总数准确性。     

A comparison of different processing methods for picked blue crab (Callinectes sapidus)

Five methods for producing picked crab meat from cooked blue crab (Callinectes sapidus) were evaluated for internal food temperatures and bacterial numbers at various process points. Whole shell-on crabs, crab cores ("backed" crabs with carapace removed), and crab meat samples were analyzed for standard plate count, total coliforms, fecal coliforms, Escherichia coli, and Staphylococcus aureus. For three of the processes, crabs were backed and washed a substantial time before picking; one of the processes used an ice slush dip to cool cooked crabs. Except for a single crab sample, bacteria were not isolated from crab and core samples. Standard plate count, E. coli, and S. aureus in crab meat samples from the different processes were statistically the same. Bacterial numbers in fresh picked crab meat samples exposed to an ambient temperature of 20 to 21.1 degrees C for 1.5 and 3.5 h and stored at 1 degrees C for 3 to 4 days and 7 to 8 days did not significantly differ (P < 0.05).