关于TTC法用于食品菌落计数适用性的研究与探讨

食品卫生细菌学检验菌落总数的测定,我们一直采用国家标准推荐的普通营养琼脂倾注平皿法。但有人用ＴＴＣ法做菌落计数,使绝大部分细菌染成红色利于计数,且对菌落总数没有影响〔１、２〕。我们发现国标法菌落计数超标样品,ＴＴＣ法的检出结果明显低于国标法。为了解作...     

检样稀释至倾注平板时间对食品中菌落总数测定结果影响的研究

〔目的〕对检样稀释至倾注平板间隔时间长短对菌落总数测定结果的影响进行研究。〔方法〕菌落总数测定采用国际法(GB4789.2—94)平板培养计数,倾注平板法。检样稀释后在不同间隔时间内,每个检样做2个平皿。〔结果〕检样从稀释后立即倾注平板开始,间隔时间越长测定的菌落总数越多。〔结论〕实验结果表明检样在稀释后立即倾注平板,与间隔20min内差异无显著性,间隔30min(含30min)差异有显著性;培养介质对细菌增长有一定影响。     

饮用天然矿泉水检验方法中菌落总数培养时间的探讨

〔目的〕探讨GB/T8538-1995饮用天然矿泉水检验方法中菌落总数的培养时间。〔方法〕对菌落总数培养时间按24h、48h、72h的变化进行分析讨论。〔结果〕饮用天然矿泉水检验方法中菌落总数培养时间应定为48h较为合适。〔结论〕48h培养后计数接近矿泉水中菌落总数的真实数量。     

阻抗法快速检测食品中乳酸菌的计数、菌落总数的研究

〔目的〕探讨用阻抗法快速测定 (18h)样品的乳酸菌、菌落总数方法的准确性、可靠性。〔方法〕建立阻抗法测定乳酸菌、菌落总数的标准曲线 ;阻抗法、国标法得出的结果重复性的测试 ;二种方法结果的比较。〔结果〕阻抗法测得的结果之间的相对标准偏差数较小 ,国标法结果之间的相对标准偏差数较大。我们用重复测量方差分析的方法 (软件SPSS 10 .0 )分析表格的数据 ,乳酸菌二种方法得到的结果之间的差异为 :F =0 .0 0 0P =0 .995 >0 .0 5 ;菌落总数二种方法得到的结果之间的差异为 :F =0 .0 95P =0 .76 >0 .0 5。〔结论〕从二种方法的重复性来看 ,阻抗法比国标法更准确 ,又从二种方法测得的结果来比较 ,P >0 .0 5两种方法无显著差异。     

菌落选点计数的新方法

目的研制菌落计数卡,探讨菌落选点计数的一种新方法. 方法应用计算机和统计学原理制作菌落计数卡,将金黄色葡萄球菌ATCC25923按103 CFU/ml-1浓度制备菌液,倾注法制作待测平皿,再分别用常法全额计数法和计数卡选点计数法进行菌落计数,将两种方法所得结果进行统计学对比分析. 结果应用自制的菌落计数卡进行选点菌落计数,其结果与应用JLQ-S1型菌落计数器作常法全额菌落计数结果相比较,其差异无显著性. 结论菌落计数卡选点计数的方法可以替代仪器常法全额计数,自制的菌落计数卡,价格低廉、制作简便、实用性强,可推广应用.     

微菌落滤膜法快速定量检测饮料中酵母

本文介绍利用混合纤维素滤膜过滤饮料样品,培养后对其上生长的微菌落进行染色和计数,定量检测饮料中酵母。14份可乐样品在滤膜上的微菌落计数与相应平板培养法计数之间相关关系为(r=0.96,P<0.01),本法迅速,不到12小时报告结果,简便,适于检测污染酵母浓度高于10~3CFU/ml的饮料。     

在化妆品菌落总数测定中应用TTC的探讨

目的：探讨在化妆品菌落总数测定中加入TTC后对结果的影响及应用TTC的安全浓度。方法：应用1～5mg／100ml TTC营养琼脂对G^-杆菌、G^＋杆菌、G^＋球菌、G^-弧菌和真菌的代表菌株进行菌落总数测定，观察菌落的生长、显色、大小变化。结果：TTC对G^-杆菌、G^-弧菌和真菌代表菌株在1～5mg／100ml内生长、显色、大小变化较少；G^＋杆菌在≤2mg／100ml、G^＋球菌在≤4mg／100ml TTC营养琼脂内生长，红色随浓度的增加而加强，菌落直径随浓度升高而变小。结论：应用5mg／100ml用于菌落计数对G^＋有明显的抑制作用，建议应用2mg／100ml的TTC浓度做化妆品菌落总数测定。     

荧光分光光度法测定食品中叶酸的含量

叶酸〔1〕是一种重要的B族维生素 ,其化学名称为蝶酰谷氨酸。叶酸的测定方法主要有微生物法〔2〕、HPLC法〔3〕、荧光法和放射免疫法〔4〕等。国标法〔5〕 测定叶酸是微生物法 ,选用的菌种可利用培养基中叶酸单谷氨酸和双谷氨酸盐进行生长 ,灵敏度较高 ,但是检测需要的时间较长。由于食品成分复杂 ,试样处理烦琐费时 ,而测定的是叶酸盐活性 ,需制备各种培养基和菌种 ,步骤多且试剂用量大 ,微生物法叶酸衍生物繁多 ,标准品来源有限 ,存在多种干扰因素 ,分析方法受到限制。本文采用超声波提取荧光分光光度法测定食品中的叶酸含量 ,方法简便…     

全自动菌落分析仪计数结果的初步探讨

目的验证国产某品牌全自动菌落分析仪的准确性和稳定性,探讨在日常工作中使用此仪器进行菌落计数的可行性。方法随机抽取28份生活饮用水进行细菌总数检验,分别通过仪器和人工计数,同时随机抽取1份水样用仪器法计数10次,对获得的数据进行对比和分析。结果仪器法与人工计数法计数结果之间具有较高相关性(r等于0.976,P等于0.000),均数间经t检验差异不具有显著性(t等于1.164,P等于0.254)。重复计数10次变异系数CV%=4.07%。结论该型全自动菌落分析仪计数结果与人工计数法没有明显区别,对饮用水菌落计数结果精确性和重复性良好、计数效率较高,在日常工作中具有一定的使用价值。     

二连浩特口岸入境交通工具消毒效果评估

〔目的〕了解全自动卫生处理设备的消毒效果,为评估该设备的应用效果提供科学依据。〔方法〕对消毒处理前和处理后的样品分别进行增菌培养,菌落计数采样方法按照《微生物检验抽样原则》(GB/T47891-2003)进行,实验室检测菌落总数参照《菌落总数标准》(GB/T4789.2-2003)方法进行。〔结果〕经检测采用自动消毒喷洒装置消毒前与消毒后杀菌效果存在明显差异。〔结论〕经检测该设备性能可靠、高效、实时性好,符合卫生处理标准,可完成消杀灭任务,适用于进出境货物和交通工具的卫生处理。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.