ATP生物发光法快速测定物体表面的菌落总数

以大肠埃希氏菌作为指示菌考量了ATP生物发光法测定物体表面卫生状况的准确性,并在实验室内模拟食品企业卫生管控,采用ATP生物发光法对具有代表性的台面进行细菌总数测定,与国家标准微生物检测方法进行了比对分析。结果显示:大肠埃希氏菌的ATP荧光值与菌落总数的线性相关性良好,相关系数R2为0.982 6;以实验室内指定台面作为盲样进行对比测定,其ATP荧光值与菌落总数的线性相关性良好,相关系数R2达到0.915 9,说明ATP生物发光法能够准确评估和测定物体表面的卫生状况。     

采用ATP生物发光法分析6株常见细菌ATP含量差异

以ATP生物发光法为基础,辅以国标平板计数法,分析和测定了大肠埃希氏菌、枯草芽孢杆菌、蜡状芽孢杆菌、乳酸链球菌、乳酸片球菌等6株常见细菌中ATP含量的差异。结果显示:当单位体积菌悬液的ATP荧光值相同时,6株细菌菌落总数无明显差异;当菌悬液的菌落总数相同时,6株细菌的单位体积菌悬液ATP含量无明显差异。研究结果同时说明ATP生物发光法能够定量测定常见区域中的细菌总数。     

ATP荧光检测法快速筛查冷荤间加工现场凉拌菜的细菌污染状况

探讨ATP(adenosine triphosphate,三磷酸腺苷)荧光检测法检测冷荤间加工食品细菌总数的可行性,为食品细菌污染现场快速检测提供科学依据。方法 从本市餐饮单位中随机抽取20家各类餐饮单位,采集4大类80份菜品作为冷荤间加工食品检测样品,分别应用ATP荧光检测法与实验室平板计数法检测细菌总数。结果 ATP荧光检测法所得菌落数与实验室平板计数法检测菌落总数对比,假阳性率18.8%,假阴性率20.4%。结论 ATP荧光检测法适用于冷荤间加工食品微生物的快速检测。     

腺嘌呤核苷三磷酸生物发光法快速检测短乳杆菌

啤酒酿造过程中的有害微生物及有机质残留检测与控制是防止微生物污染、保障啤酒质量的主要控制因素。该文以腺嘌呤核苷三磷酸(adenosine triphosphate,ATP)生物发光法为基础,建立啤酒酿造过程中微生物污染风险的快速评估方法。采用便携式ATP荧光检测仪对表面人工污染的短乳杆菌、梯度稀释的短乳杆菌菌悬液和啤酒有机质残留进行检测,分别对相对荧光单位(relative luciferase unit,RLU)和表面细菌总数、细菌浓度和啤酒有机质残留进行相关性分析,并建立预测模型。结果显示,表面细菌总数、水质细菌浓度和啤酒有机质残留预测模型的相关系数均> 0.9(P <0.05),其中啤酒有机质残留预测模型的相关系数最高(R²=0.994)。基于便携式ATP快速荧光检测系统建立的表面短乳杆菌总数、水质短乳杆菌浓度和啤酒有机质残留预测模型,可对啤酒酿造过程中卫生学检验提供有效的实时监控,也为ATP生物发光法在食品质量安全的应用提供了理论支撑。     

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。     

ATP生物发光法快速测定生乳中微生物总数的研究

对ATP生物发光法应用于生乳中微生物检测进行了初步摸索,确定了加体细胞裂解液次数为三次;乳样最佳稀释倍数为20倍;用ATP生物发光法对大批乳样进行检测,同时用国标法进行了平皿菌落培养,结果显示,乳中微生物总数对数与光值对数呈正的直线相关(r=0.9485),相关程度为显著相关(P<0.001),二者回归方程为Y=1.0496x 2.4.     

流式细胞技术检测酸性饮料中菌落总数的研究

利用流式细胞技术(Flow Cytometry,FCM)检测酸性饮料(pH<4.6)中的菌落总数并与平板法和滤膜法进行比较分析,建立FCM快速检测酸性饮料中菌落总数的方法。选择13种常见实验菌株,通过人工加菌实验进行验证。结果表明,基质和含菌量对FCM法的检测结果影响较大,酸性饮料中的部分菌株难以直接被FCM法检出,需经过滤富集菌于中性TSB肉汤中36 ℃培养22 h排除基质和含菌量低的影响,培养后的菌溶液经FCM法与平板法检测结果均在一个数量级。运用AOAC官方分析方法对酸性饮料中不同浓度13种实验菌株滤膜法和增菌22 h后FCM法的定性检测结果进行统计学分析,卡方值X2<3.84,同时假阴性率=1.9%<2%,假阳性率=4.2%<9.6%,说明FCM法可替代滤膜法进行酸性饮料中菌落总数的定性检测,用于产品的快速放行。     

ATP法测定奶中的细菌含量

为了评价ATP法在UHT奶中菌藩总数和商业无菌检测的实用性,本研究通过检测UHT乳中ATP本身的含量,以及微生物平板计数法和商业菌落总数Petfifilm俐测试片法对样品进行菌落总数和商业无菌检测,建立样品中ATP含量与菌落总数的对应关系。结果表明,不同品类UHT牛奶中ATP法结果与菌落总数Petrifilm^TM测试片法和国标平板计数法结果的相关性强,复现性好。由此可知,ATP法可以作为一种快速检测UHT奶中菌落总数和商业无菌的方法。     

ATP荧光微生物快检法中不同材质及孔径微孔滤膜细菌截留效果的评价

在相同的操作条件下考察了直径13 mm的混合纤维素酯膜、聚碳酸酯膜、醋酸纤维素膜、硝酸纤维素膜等4种常用微孔滤膜对细菌的截留能力。以细菌总数含量为10 CFU/m L的水样为待测样品,过滤体积为50m L,过滤测定5次。当孔径为0.22μm时,4种滤膜的平均截留率依次为100%、94%、84%和72%;当孔径为0.45μm时,4种滤膜的平均截留率依次为92%、82%、70%和70%。因此,孔径为0.22μm的混合纤维素酯膜对细菌的截留效果最好。以该滤膜过滤细菌总数含量为42 CFU/m L、20 CFU/m L、10 CFU/m L、4 CFU/m L的水样各50 m L,然后以ATP生物发光法测定膜上细菌,所得ATP荧光值与细菌浓度的线性相关系数R20.9,线性相关性较好。结果显示,0.22μm的混合纤维素酯膜能够满足ATP生物发光法对微菌含量样品的富集测定要求。     

生物发光法快速检测食品中活菌总数

生物发光法检测食品中活菌总数具有快速、简便、灵敏等优点,经与常规的平板计数法比较,结果无明显差异,可作为食品生产过程中快速微生物监测手段。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the