应用DNA彗星试验技术检测辐照鸡肉的研究

[目的]研究DNA彗星试验技术在检测辐照鸡肉方面的应用.[方法]新鲜鸡肉,于-20℃冷冻保存7天后,分别用0kGy、1kGy、3kGy、5kGy和7kGy不同剂量进行辐照处理,解冻后分离细胞,用彗星试验测定其DNA损伤,并分析剂量反应关系.[结果]经0kGy、1kGy、3kGy、5kGy和7kGy辐照的鸡肉细胞平均尾长和尾相分别为1.02μm、2.19μm、2.88μm、3.53μm和4.11μm以及0.38、0.75、1.05、1.60和2.03.经统计学分析,辐照与未辐照鸡肉细胞彗星电泳图尾长与尾相存在显著性差异,并存在一定的剂量反应关系.[结论]彗星试验可检测由于辐照对于鸡肉组织细胞的DNA损伤,并可作为筛选技术判断该鸡肉是否经过辐照处理.     

LAL／GNB法筛选辐照鸡肉的应用研究

【目的】探讨内毒素检测（LAL）与革兰氏阴性菌计数（GNB）相结合的方法应用于辐照鸡肉的筛选的可能性。【方法】市售鸡肉丁以50g每份分装后,以γ射线进行辐照处理,剂量分别为0kGy、2kGy、6kGy,每个剂量各12份,通过革兰氏阴性菌的培养计数估计样品中存在的活的革兰氏阴性菌的量,通过内毒素浓度定量估计活的和死亡的革兰氏阴性菌总量,比较两者差异来判定是否经过辐照处理。[结果】辐照剂量为6kGy时,12个样品被检测出经过辐照处理。辐照剂量为2kGy时,8个样品被检测出经过辐照处理,4个样品检测出未经过辐照处理。辐照剂量为0kGy时,12个样品检测结果均为未经过辐照处理。【结论】LAL／GNB法可以应用干辐照鸡肉的筛选。     

PCR—SSCP检测水稻SNPs

本文选择5个水稻SNPs位点为对象,研究凝胶组成和电泳条件等对PCR-SSCP检测SNPs的影响.发现凝胶浓度、交联度、甘油和电泳温度等均可明显影响DNA单链分子迁移率,且对不同DNA单链分子的影响程度不同.因此,可以通过调节凝胶浓度、交联度、甘油和电泳温度等提高PCR-SSCP检测水稻SNPs的分辨率及效果.在一定条件下,较低交联度和4°电泳条件检测SNPs的效果更好.     

转Bt基因作物恒温扩增快速检测技术

[目的]建立一种快速检测转Bt基因作物的方法。[方法]利用Bt的Cry1ab/ac基因序列设计特异性引物,建立LAMP检测方法以及优化反应体系,并进行LAMP的特异性和灵敏度试验。[结果]成功建立转Bt基因作物的LAMP检测方法,得到最优的反应体系。在特异性试验中,转Bt基因作物基因组DNA均呈阳性,而非转基因作物、转Bar基因作物、转CPTI基因作物、转EPSPS基因作物等均为阴性;在灵敏度试验中,转Bt基因作物的最低检测限为10个拷贝。[结论]LAMP方法具有很高的特异性和灵敏度,可用于转Bt基因作物的现场快速检测。     

细菌快速检测与传统培养方法结果比较

[目的]比较细菌快速检测试纸片与传统方法在细菌检测结果上的差异。[方法]检测同一样品的细菌总数和大肠菌群2个指标。细菌总数检测分别以平板计数法和细菌总数试纸片进行,大肠菌群分别以多管发酵法和大肠菌群快速检测纸片法进行。[结果]以平板计数法检测细菌总数,37℃培养48h能观察出结果; 而同一样品用市售的2种细菌总数试纸片37℃培养48h显示不出结果,需要延长培养时间至72h以上; 多管发酵法检测大肠菌群24h能观察到结果,延长时间培养阳性结果不变; 用大肠菌群快速检测试纸片,36h才能观察到结果,延长培养时间,阳性结果随之变化; 传统培养方法与试纸片法的结果经统计处理差异有显著性。[结论]细菌快速检测试纸片能简化操作,但成本高,培养时间长,灵敏度低。     

多重PCR检测食品中转基因成分研究

[目的]建立检测转基因食品的多重PCR-聚丙烯酰胺凝胶电泳快速检测体系.[方法]针对转基因大豆、玉米、油菜的多个相对稳定的转基因元件,包括35S、NOS、EPSPS、Cry1A、NPTⅡ等基因,同时选定植物本身固有的大豆Lectin、玉米IVR、油菜Napin基因作为内源参照指示基因,设计、筛选出9对引物分别组成多重PCR,结合高灵敏度的聚丙烯酰胺凝胶电泳组成快速检测体系,对转基因食品进行检测,1～2天能完成整个检测过程.对珠海地区市售的大豆、玉米、油菜及其加工产品共185个样品中的转基因成分进行了初步调查.[结果]建立的多重PCR检测体系稳定可靠、特异性好,灵敏度高.调查的185份可疑食品样品中,转基因阳性率达27.6%.[结论]该检测体系快速可靠、灵敏准确、特异性好,且操作简便、成本低廉,是一种进行转基因食品检测的良好的技术模式.对珠海地区的转基因食品状况有了一定了解.     

二喹啉甲酸法在食品加工用具蛋白质残留现场快速检测的应用

[目的]探讨二喹啉甲酸法现场快速检测食品加工用具上蛋白质残留的应用前景。[方法]以棉签为反应载体,通过检测限测定试验、反应时间条件试验、还原性物质干扰试验和现场应用试验,研究二喹啉甲酸法检测蛋白质的检测限、干扰因素和实际应用情况。[结果]棉签二喹啉甲酸法能检测50μg以上的蛋白质,5000μg的3种还原糖、低于2μg的维生素C和5μg维生素B1不会产生干扰。[结论]棉签二喹啉甲酸法方法简便,结果直观,检测限低,是现场快速检测食品加工用具蛋白质残留的理想方法。     

微波消解测定食品中Pb、As等金属元素方法的研究

[目的]探讨微波密闭消解在食品中重金属元素检验的前处理方法.[方法]对微波消解法进行了精密度、回收率等实验.[结果]方法的回收率90%-105%,相对标准偏差1.0%-3.7%.[结论]微波密闭消解法对一般食品中Pb、As、Hg等金属元素检测的样品处理有良好的效果,优于湿式消解法,能满足快速分析的要求.     

荧光定量PCR法检测中国籍海员血清HBV DNA

[目的] 了解远洋海员HBV DNA的实际感染情况,为国境口岸传染病监测策略提供基础数据.[方法] 选广州某口岸2003年3月至12月中国籍远洋海员体检血清标本192例,用ELISA法检测192份血清乙肝五项免疫学指标,以HBSAG阳性121例为实验组,51例HBSAG阴性为对照组.用实时荧光定量PCR法同时检测HBV DNA病毒含量.比较两组HBVDNA检出差异.[结果] 192名远洋海员HBVDNA检出78例(40%).5项血清免疫学指标和HBV DNA全部阴性18例.实验组HBV DNA阳性64例(50.02%),对照组HBVDNA阳性14例(27.45%),两组差异有显著意义(χ2<0.01).14例HBSAG阴性HBV DNA阳性血清中,现行法规规定的三项传染性指标均为阴性,核心抗体均为阳性.[结论] 三项传染性指标阴性的人群仍有传播HBV的危险,建议有关部门修订远洋海员等特殊人群乙肝防治政策,直接检测HBV DNA.     

蔬菜中低含量有机磷农药残留的快速检测

1前言 农药残留严重导致损害人类的健康.为此,很多国家对于高毒高残留农药作出了最严格的限制. 蔬菜中有机磷农药残留的检测,主要有气相色谱法(GC)[1-3]和生物技术法.生物技术法包括免疫法[4],生物传感器法[5,6]及植物酯酶片法[7],而免疫法及生物传感器方法目前还未商品化,植物酯酶片法虽然有市售试剂盒,而且检测快速,简便,可其灵敏度不高,通常只能检测残留量在2mg/kg以上的样品,因此不能满足低残留量(≤0.05mg/kg)检测要求.     

十二种食源性致病菌可见光基因芯片检测方法的建立

[目的]利用可见光基因芯片技术,针对12种常见食源性致病菌,建立快速、准确、高通量的诊断方法。[方法]设计靶细菌16S rDNA和23S rDNA的通用引物,反向引物5’端标记生物素;特异寡核苷酸探针设计在两对引物之间的可变区,5’端标记氨基基团。将探针点样于固相载体制备基因芯片,优化PCR反应体系后,PCR产物与芯片点制探针区域进行杂交,然后通过化学显色直接观察结果,并评价反应体系的特异性、灵敏度、重复性等指标。收集临床样本28例,同时制备双盲模拟污染样本10例,对检测方法进一步评价。[结果]：本试验所建立的基因芯片方法可同时检测志贺菌、耶尔森氏菌、沙门菌、腊样芽孢杆菌、空肠弯曲菌、金黄色葡萄球菌、霍乱弧菌、副溶血性弧菌、单增李氏菌、布鲁氏菌、变形杆菌、肠出血性大肠杆菌O157：H7等12种食源性致病菌,特异性高,操作简便;针对纯培养食源性致病菌反应体系的灵敏度为10^3cfu/mL,模拟样本的灵敏度为10^4cfu/mL;重复性好;采用可见光基因芯片方法检测28例临床样本,26例与常规培养方法结果完全一致,符合率达到92.9%;双盲模拟样本的检测符合率达到100%。     

气相色谱及气相色谱-质谱法检测食品中增塑剂

利用气相色谱及气相色谱-质谱联用技术,对食品中4种邻苯酸二甲酯类化合物进行检测。对于非油脂类食品,气相色谱法的检出限为1.5mg/kg,平均回收率为67.4%-92.9%,相对标准偏差为1.6%-4.7%;气相色谱-质谱联用的检出限为0.05mg/kg,平均回收率为66.3%-112.9%,相对标准偏差为2.9%-11.3%。对于油脂类食品,气相色谱法的检出限为30mg/kg,平均回收率为73.4%-96.1%,相对标准偏差为1.6%-2.8%;气相色谱-质谱联用的检出限为1.5mg/kg,平均回收率为64.1%-80.2%,相对标准偏差为1.6%-4.5%。用该分析方法对285批食品样品进行了分析检测,1批食品样品检出BBP,13批检出DBP,63批检出DEHP,总检出阳性样品68批,总阳性检出率23.9%,其检出质量分数为0.05-1.27mg/kg。该方法前处理简单,分离效果好,灵敏度高,能够满足食品中4种邻苯二甲酸酯检测的需要。     

婴幼儿食品微生物及微生物毒素调查分析

对婴幼儿食品（配方乳粉、补充谷物、饼干和罐头）分别进行微生物污染以及微生物毒素调查。调查结果表明：357份婴幼儿食品均未检出沙门氏菌和单核细胞增生李斯特氏菌;11份婴幼儿配方乳粉、1份补充谷物和1份饼干食品中检出坂崎肠杆菌,检出率分别为4.2%,2.4%和2.5%;检出1份补充谷物菌落总数超过国家标准最高安全限量值。13份婴幼儿配方乳粉和3份补充谷物检出肠杆菌科细菌,检出率分别为32.5%和7.1%;14份（婴幼儿）配方乳粉、2份婴幼儿罐头检出蜡样芽孢杆菌,检出率分别为35%和20%;1份婴幼儿配方乳粉检出黄曲霉毒素M1超标。婴幼儿食品存在微生物及其微生物毒素污染的风险,应加强对婴幼儿食品的致病微生物及其毒素的监测和监管。     

Thoughts,attitudes and profile of Brazilian consumers regarding food irradiation

This study aimed to examine the neophobia, knowledge, thoughts, and opinions related to food irradiation among consumers living in a small city in Brazil through the application of a behavioral and sociodemographic questionnaire. It was found that the 271 respondents had little knowledge about the process of food irradiation and had low intent to purchase irradiated food; several consumers associated irradiated food with radioactivity and cancer. Individuals with better knowledge about irradiation and those who are young, single, did not live with children, and had higher levels of education and higher monthly family incomes were more likely to buy irradiated foods than others. These results describe the profile of potential consumers of irradiated foods and the knowledge, thoughts and opinions of the residents of a small city relative to food irradiation. This data could assist industries that irradiate foods to adopt strategies that ensure greater acceptance of their products.     

Consumer acceptance of irradiated food and information disclosure – A retail imperative

There is substantial contribution in the literature for understanding the complex nature of irradiated foods, the growing importance and the controversial views expended by consumers, yet acceptance of these foods for many have not met with optimal recognition. The study extends the theory of planned behaviour antecedents to analyse independent determinants and the influences of risk and trust. The indirect effects are also examined. The study uses multigroup analyses to identify whether consumer's concerns on information for irradiated foods act as moderators in order to provide a better explanatory power.The data was analysed using Structural Equation Modelling on responses obtained from a sample of 322 consumers. The study found that the theory of planned behaviour antecedents successfully predicted behavioural intention for irradiated foods but with some limitations. The findings also demonstrate additional support to show that the robustness of the TPB framework is effective for irradiated foods and addresses the literature calls on research for more theoretical underpinnings. It further addresses retailer implications, as the ultimate decision falls with retailers who assess whether sales for irradiated foods are acceptable depending on consumer demand.     

脱氧雪腐镰刀菌烯醇毒性和检测方法研究进展

本文综述了脱氧雪腐镰刀菌烯醇毒素的毒理以及在世界各国的有关现状,介绍了国内外食品检测中该毒素的提取、纯化和定量检测的最新进展及存在问题,建议应加强对国内市场食品特别是进出口食品中该毒素的检测。     

酶联免疫吸附法检测水产品中的氟苯尼考

氯霉素被禁用于动物性食品后,作为氯霉素类药物的氟苯尼考,在畜牧业中得到广泛应用,对畜禽疾病的控制和治疗起到了重要的作用。随着研究的深入,发现氟苯尼考也有许多毒副作用。因此,必须控制氟苯尼考在动物性食品中的残留,以保障消费者的健康。酶联免疫检测法(ELISA)是一种简便、快速、并适合大规模样品筛选的检测方法。本实验运用ELISA方法检测肉类中残留的氟苯尼考含量,并得到该方法检测的灵敏度、检测下限、交叉反应率、结果重现率等数据,之后用LC-MS对ELISA实验数据进行方法确认。发现运用ELISA检测鱼、虾、肉类中氟苯尼考残留的检测限可低至0.1μg/L,回收率可达70%~120%,重复性好,且实验数据与LC-MS的数据相关性达到99.98%,这表明ELISA是一种检测鱼、虾、肉类食品中氟苯尼考残留的可靠方便的方法。     

Food consumption,lifestyle patterns,and body mass index of a group of white South African students

There is worldwide concern that higher education students are increasingly engaging in unhealthy eating and lifestyle practices. A total of 488 white students participated in a study aimed at investigating the current food consumption and related lifestyle patterns of students at a South African residential university. The respondents’ self‐reported weight and height was used to calculate their body mass index (BMI). Closed and open‐ended questions measured aspects of the respondents’ usual eating patterns and lifestyles. The meal patterns and composition confirmed Western‐orientated food practices, as the majority consumed three meals a day, with in‐between meal snacking, and a different meal pattern over weekends. Respondents’ food intake was further characterized by a low intake of fruit, vegetables, and dairy products and frequent consumption of foods high in fat, sugar, and sodium. Although the majority (66.8%) of the study group were classified as normal weight according to their BMI, when comparing males and females, more males than females were overweight and obese. Only 54% of the males had a normal weight compared to 82% of the females. There was, however, no statistically significant difference (p = 0.149) between how males and females in the different BMI groups felt about their weight. The study also explored the relationships between the respondents’ BMI, gender, food consumption patterns, and type of residence. The features of the food consumption patterns were depicted according to whether breakfast was eaten or not; snacking activity between meals; the consumption of ready‐prepared convenience meals, fast foods; home‐cooked meals; and eating out. There were no statistical significant differences between the BMI categories of males and females regarding their habit to eat breakfast or not; and to snack between meals either during the morning, in the afternoon or after supper. Similarly, no statistical significant differences were noted when relating the BMI categories of the gender groups to the frequency of consumption of ready‐prepared, convenience type meals, fast foods, and home‐cooked meals. However, a statistical significant difference (p‐value 0.006) was found between BMI categories per gender and general frequency of eating out. No statistical differences was noted between BMI categories, gender and place of residence irrespective of the type, whether the student lived with parents, independently in a flat or apartment, or a house with friends or a room, or in a university residence.     

Students' patronage and views on the operations and services of food vendors

Abstract Vendors of meals and snacks, granted the realities of the present changing economic and social lifestyles, will continue to feed large numbers of people despite the insanitary conditions under which most of them operate. This study sought to find out the degree of patronage of food sold by vendors, items purchased, reasons for patronizing, views and opinions on the services patronized. Two-hundred and forty-five students resident in five halls at the University of Ghana completed a self-administered questionnaire each. Eighty-six per cent purchased cooked meals and snacks regularly from vendors. Over two-thirds consumed their meals at the selling sites. However, the services and facilities offered by vendors were judged as inadequate and poor. Nineteen per cent reported having suffered diarrhoea, stomach aches, indigestion and other gastrointestinal problems as a result of eating vendored foods. Three outstanding reasons emerged for the high patronage of vendored foods. They are food always being available (69%); food being cheaper (62%); and more variety to choose from (42%). These findings portray the great influence of money and time on consumer choice of food in our present harsh economic environment. Patrons indicated several unhealthy practices by vendors that pose health threats to patrons. These observations together with several recommendations made regarding the safe handling of food, water and the environment indicate consumers' awareness of the need for safe delivery of the food they consume. There is the urgent need therefore to organize and train vendors, pass a food law, supervise operations of vendors and also educate consumers to choose only safe food and water and insist on a clean food environment.