SD-PMA-qPCR快速检测冷冻肉制品中活性沙门氏菌的研究

为实现冷冻肉制品中活性沙门氏菌的快速检测与控制,本文利用PMA（叠氮溴化丙锭）和SD（脱氧胆酸钠）消除死菌和损伤菌的影响,建立了运用SD-PMA-qPCR法检测活性沙门氏菌的反应体系和反应条件,并进行人工染菌样品检测试验。SD的最佳浓度确定为0.1%,最佳孵育时间为20 min。对-20 ℃低温冷冻处理3~4 d的沙门氏菌处理液,使用平板计数法、qPCR、PMA-qPCR和SD-PMA-qPCR进行计数,结果发现qPCR与PMA-qPCR二者检测值接近且明显高于平板计数值,而SD-PMA-qPCR检测值与平板计数值相近,这表明SD和PMA的联合使用能有效的消除死菌和损伤菌的影响。人工染菌样品试验表明,沙门氏菌检出限在102 CFU/g,同时106 CFU/g大肠杆菌O157:H7的存在不会影响检测结果。本研究所建立的SD-PMA-qPCR检测方法特异性好、灵敏度高,有望成为快速检测冷冻肉制品中活性沙门氏菌的新方法,具有很好的研究价值和应用前景。     

次氯酸钠诱导肠炎沙门氏菌活的非可培养状态形成及复苏过程研究

目的 研究不同有效氯浓度次氯酸钠溶液诱导肠炎沙门氏菌进入活的非可培养状态（viable but non-culturable state: VBNC）及复苏条件研究。方法 以不同有效氯浓度次氯酸钠处理肠炎沙门氏菌,分析肠炎沙门氏菌活的非可培养状态菌数及VBNC发生率的变化,结合扫描电镜观察肠炎沙门氏菌VBNC态细胞与正常细胞的形态差异,而后比较不同复苏条件的复苏效果,同时对复苏后的细胞生理活性进行评价。结果 40 mg/L有效氯浓度处理20 min可使活菌全部进入VBNC状态,细胞表面出现褶皱塌陷;高于60 mg/L有效氯浓度可全部杀灭,细胞出现断裂、破损;进入VBNC态的肠炎沙门氏菌在5种复苏处理下,均可恢复可培养性;在20 mmol/L丙酮酸钠×热激条件下恢复效果较好。pHi和胞内ATP显示复苏后细胞活性较正常细胞有所降低。结论 在食品生产、环境清洁中应注意次氯酸钠使用浓度,否则极易造成肠炎沙门氏菌VBNC态的形成和复苏,导致食品污染,从而增加食品安全风险。     

活的非可培养状态细菌的培养和复苏条件的研究

本文研究食品常用的消杀条件对大肠杆菌和金黄色葡萄球菌进入活的非可培养状态(viabile but nonculturable,VBNC)的诱导,并探讨高温诱导的VBNC菌的复苏条件。将对数生长期的大肠杆菌、金黄色葡萄球菌通过温度、盐度以及不同浓度的山梨酸钾处理进行诱导;对高温条件诱导的VBNC菌液添加维生素类物质,研究复苏VBNC菌的条件。结果表明,大肠杆菌在-20℃培养可形成VBNC菌,在温度超过65℃水浴30 min 存在VBNC菌; NaCl浓度大于15%环境下培养15ｄ可诱导VBNC菌的形成;山梨酸钾浓度高于0.15％即可诱导大肠杆菌进入VBNC;金黄色葡萄球菌在相同条件下诱导菌落数变化缓慢,未出现VBNC菌。复苏研究中,添加0.1‰-0.18‰范围的维生素C或0.252%的泛酸或0.06‰生物素可使VBNC的大肠杆菌复苏;VBNC的金黄色葡萄球菌复苏则需要添加0.2‰-0.25‰范围的维生素C或0.248%的泛酸或0.06‰生物素。本研究表明食品的消杀条件均有形成VBNC菌的可能,不同属的VBNC菌复苏在相同复苏物质条件下所需的浓度不同。为保证食品安全在食品检测环节可通过添加复苏条件以确保检测结果的准确性,或在运输储藏过程中避免复苏物质的存在,本研究有望为企业对食品的消杀处理以及检测、储藏运输等条件改善提供科学依据。     

食源性微生物VBNC状态检测与分离方法的研究进展

在环境胁迫下,部分食源性微生物(大肠杆菌、沙门氏菌、金黄色葡萄球菌、乳酸菌和酵母等)会进入活的非可培养状态(Viable but non-culturable,VBNC)得以存活。进入VBNC状态的微生物在细胞形态、代谢活性以及致病性等方面发生了变化,并且不能用常规的方法将其检出,因此给食品质量与安全带来了极大的挑战。本文总结了食源性微生物VBNC状态的发展趋势;简单介绍了食源性微生物VBNC状态的各种环境诱导因素、生理生化特性和复苏条件;着重论述了应用于食源性微生物VBNC状态的分子检测技术和噬菌体检测法,并讨论了方法的优缺点及优化方案。此外,本文还总结了分离和纯化VBNC状态微生物的方法并分析了方法的可行性,以期为进一步探究食源性微生物VBNC状态的生理特性,研发更加快速、简便和高效的检测分离方法提供参考。     

VBNC状态啤酒易感乳杆菌的诱导及复苏

本文研究了一种典型的难培养啤酒易感乳杆菌-耐酸乳杆菌(Lactobacillus acetotolerans)形成"活的但不可培养"(VBNC)的诱导方式,以及从此状态复苏至可培养状态的方法。将培养至对数期的耐酸乳杆菌2011-11菌株采用啤酒内连续传代驯化法还原其在啤酒酿造过程中的实际生存状况,并通过荧光染料染色对诱导后的耐酸乳杆菌细胞进行活性检测;利用逐步升温和添加促进物法对VBNC菌进行复苏试验。当连续传代至第19代,MRS检测平板上可培养菌数降为零,此时菌体多数仍存在呈现绿色荧光的活细胞,表明耐酸乳杆菌已形成VBNC状态,且仍具有污染啤酒能力;将刚进入VBNC状态的耐酸乳杆菌菌悬液经过氧化氢酶处理后涂布于MRS平板,于26℃厌氧培养,可使耐酸乳杆菌复苏至可培养状态。本研究证实,可通过啤酒内连续传代诱导获得VBNC状态耐酸乳杆菌,而添加过氧化氢酶改良常规MRS平板是一种有效的复苏方法。     

肠炎沙门氏菌EMA-PCR检测方法的建立

将荧光染料叠氮溴化乙锭（ethidium monoazide,EMA）与聚合酶链式反应（polymerase chain reaction,PCR）检测技术相结合,用于肠炎沙门氏菌活菌的检测。实验参数优化结果表明,当EMA终质量浓度50 μg/mL、曝光时间10 min时,可以抑制约107 CFU/mL肠炎沙门氏菌死菌DNA的扩增;活菌灵敏度检测结果显示,EMA-PCR方法检测限与单一PCR方法一样均为27.5 CFU/mL,说明EMA处理既不会影响活菌DNA的扩增也不会影响PCR方法的灵敏度。利用EMA-PCR方法检测死活混合菌液时发现,添加EMA的实验组DNA条带亮度会随着活菌比例的降低而变暗,且当样品中全是死菌时,没有目标条带出现;而不添加EMA的对照组DNA条带亮度没有变化,当样品中全是死菌时,目标条带依然清晰可见。说明添加EMA可以达到区分死活菌的目的,EMA-PCR方法只检测样品中的活菌,避免了死菌DNA造成假阳性的可能性。     

食源性致病菌活的不可培养状态研究进展

在食品加工、产品运输及贮藏过程中,极端的环境条件可能会导致食品中的致病菌进入活的不可培养(viable but non-culturable,VBNC)状态,如大肠杆菌O157:H7、副溶血性弧菌、沙门氏菌、金黄色葡萄球菌等常见的食源性致病菌。食源性致病菌一旦进入了VBNC状态,常规的培养检测方法不能将其检出,易造成VBNC状态致病菌漏检,威胁食品安全和人体健康。本文归纳了食品加工过程中可能致使食源性致病菌进入VBNC状态的相关因素,概括了食源性致病菌VBNC状态的生物学特性,并着重介绍VBNC食源性致病菌的检测方法,以期为食源性致病菌的安全防控提供科学依据。     

多重PCR检测4种常见食源性致病菌

目的 建立一种多重聚合酶链式反应法(multiplex polymerase chain reaction, MPCR)快速检测肉制品中金黄色葡萄球菌、沙门氏菌、志贺氏菌和单增李斯特氏菌的分析方法。方法 选取金黄色葡萄球菌nuc基因、沙门氏菌SipB基因、志贺氏菌ipaH基因、单增李斯特菌inlA基因作为目标基因, 设计4对PCR引物, 建立并优化多重PCR反应体系, 评价该体系的特异性和灵敏度, 并对人工污染的熟肉样品进行检测。结果 构建的多重PCR方法特异性强、灵敏度高, 人工污染熟肉匀浆中4种致病菌的检出限为103 CFU/mL。结论 构建的多重PCR检测方法能够快速、准确、高效地检测肉制品中金黄色葡萄球菌、沙门氏菌、志贺氏菌和单增李斯特氏菌, 为食源性疾病菌的快速检测提供参考依据。     

3种沙门氏菌检测方法能力验证

目的比较国标法、VETIK和荧光定量PCR法3种沙门氏菌检测方法的检测效果。方法 10份盲样经GB4789.4-2010《食品安全国家标准食品微生物学检验沙门氏菌检验》、实时荧光定量PCR方法和VIDAS仪器检测,生化部分用VITEK2 compact执行。结果国标法在10个盲样中检出3种血清型沙门氏菌,分别为5号样品检出阿贡纳沙门氏菌、7号样品检出蒙得维的亚沙门氏菌和肯塔基沙门氏菌。VETIK和荧光定量PCR法检出5号和7号呈沙门氏菌阳性,其他为阴性。结论 VIDAS和实时荧光PCR检测方法快速、可靠、灵敏度高,可作为传统检测方法有效补充。     

奶粉中沙门氏菌和阪崎肠杆菌的测定能力验证结果分析

目的 提高实验室用传统生化方法检测沙门氏菌和克罗诺杆菌属(阪崎肠杆菌)的能力和水平。方法 用空白添加法和交叉试验检查培养基性能后,以奶粉样品为材料,用传统生化培养方法进行检测。结果 发现在传统生化检测技术中,对于排除非沙门氏菌来说,BS板作用突出,XLD和沙门氏菌显色平板容易受干扰菌影响。W样品检出沙门氏菌,Q样品未检出沙门氏菌;V样品检出阪崎肠杆菌,G样品未检出阪崎肠杆菌。结论 通过该研究,本实验室的沙门氏菌和克罗诺杆菌属(阪崎肠杆菌)的传统生化检测技术水平和能力得到了提高。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press