产细菌素乳酸菌的筛选与鉴定

利用溶钙圈法及牛津杯双层平板法,从欧洲萨拉米香肠、新疆奶酪、自发酵泡菜和韩式辣白菜中分离筛选产细菌素的乳酸菌,通过形态学、生理生化鉴定、16S rDNA将菌株鉴定到种,并对其细菌素基因进行克隆,确定细菌素种类。结果表明:从分离纯化到的206株乳酸菌中筛选出抑菌效果较好的菌株SA102、SA104、N105、N107、N108,在排除酸、过氧化氢等干扰因素后,菌株所产抑菌物质对蛋白酶敏感,初步判定起抑菌作用的是细菌素。16S r DNA结果表明这5株产细菌素的菌株2株为乳酸乳杆菌,3株为植物乳杆菌,通过设计引物对菌株细菌素基因进行PCR快速筛选,结果表明菌株N107、N108含有IIb类细菌素Plantaricin KJ基因编码序列,生理生化指标测试证实这些产细菌素菌株不产气、不产氨、不产硫化氢、不产粘、不产色素,具有较好的生物安全性。最后对发酵液中细菌素粗提物的酸碱稳定性和温度稳定性进行了初步探究,以期为将来细菌素的进一步实际应用提供一定的理论借鉴。     

一株产广谱细菌素乳酸菌的筛选与鉴定

为获得产广谱细菌素的乳酸菌,采用经典的乳酸菌筛选法及16S rRNA基因序列测定法,从传统酸白菜中分离乳酸菌并进行菌种鉴定,从蛋白酶稳定性、热稳定性、pH值稳定性和抑菌谱4个方面分析抑菌物质的生物学特性。结果表明,从传统酸白菜中分离出1株产抑菌活性物质的乳酸菌SY5,经鉴定为戊糖乳杆菌(Lactobacillus pentosus)。将发酵上清用蛋白酶K和胃蛋白酶处理后抑菌活性丧失,表明抑菌活性物质具有蛋白质性质,确定为细菌素。生物学特性分析表明,该细菌素在120℃热处理30 min后仍保留82.7%的抑菌活性,pH值范围为2～7。抑菌谱测定结果表明,该细菌素对多种革兰氏阳性菌和革兰氏阴性菌均有较好的抑制效果,具有广谱抑菌活性。     

传统牦牛酸奶中产细菌素乳酸菌的筛选及鉴定

采用溶钙圈法对来自青海海南藏族自治区、四川阿坝、甘孜理塘的牦牛酸奶样品的菌株进行分离筛选，采用形态学观察和16S rRNA序列分析进行鉴定；测定筛选菌株上清液对金黄色葡萄球菌（Staphylococcus aureus）、大肠杆菌（Escherichia coli）抑菌活性；考察筛选菌株上清液对蛋白酶的耐受性及对抗生素的敏感性，并确定细菌素种类。结果表明，共分离筛选出6株菌（编号为A1～A2及G1～G4），其中菌株A1～A2被鉴定为嗜热链球菌（Streptococcus thermophilus），菌株G1～G4被鉴定为屎肠球菌（Enterococcus faecium）；菌株G3对金黄色葡萄球菌、大肠杆菌的抑菌圈直径＞20 mm，且对蛋白酶不耐受，表明该菌株产细菌素，对常见抗生素敏感，经细菌素基因鉴定证实，该菌株产肠球菌素A和肠球菌素P。综上，菌株G3可作为产细菌素益生菌的候选菌株。     

藏灵菇中乳酸菌的鉴定及细菌素生物特性研究

从藏灵菇中筛选出一株具有抑菌活性的菌株,采用生理生化鉴定、16S rDNA序列分析确定菌种属性,采用硫酸铵沉淀法对该菌所产生的细菌素进行粗提取并对其抑菌活性和稳定性进行研究。结果显示,该菌为植物乳杆菌,除去有机酸和过氧化氢的影响,该菌产生的细菌素具有较好的抑菌活性。该菌所产的细菌素热稳定性较好,在100℃处理30 min抑菌活性降至54%,且对酸碱不敏感,在p H3~9的范围内都具有抑菌活性,在p H为3.82时抑菌活性最佳,对胃蛋白酶、α-凝乳酶有较强的耐受性,对蛋白酶K较敏感,在37℃下处理2 h抑菌活性为处理前活性的47.36%。对植物乳杆菌产细菌素的分析证明该菌产的细菌素在食品加工防腐中具有潜在的使用价值。     

一株从泡菜中分离的产细菌素乳杆菌的鉴定及细菌素特性研究

从泡菜中分离的329 株乳酸菌中,筛选出一株产细菌素的乳酸菌,编号为SD-22。经生理生化实验鉴定为短乳杆菌(Lactobacillus brevis)。在排除过氧化氢干扰和有机酸抑菌作用后,brevicin SD-22 对革兰氏阳性细菌和革兰氏阴性细菌具有较好的抑制作用,对部分真菌也有抑制作用,但对酵母菌和青霉无抑制作用,具有良好的热稳定性和pH 值稳定性,经胰蛋白酶、胃蛋白酶和蛋白酶K 处理后抑菌活性完全消失,对α- 淀粉酶不敏感。因此初步认为该菌株是一株产广谱细菌素的乳酸菌。     

乳酸菌中抗李斯特细菌素的筛选及理化性质分析

从鱼肉丸中分离筛选到1株具有抑菌活性的乳酸菌菌株Y153,对单核细胞增生李斯特菌ATCC54003的生长具有良好的抑制作用。16SrRNA序列同源性分析鉴定乳酸菌Y153为乳酸链球菌属（Streptococcus）。在排除有机酸、过氧化氢的干扰后,确定该抑菌物质为蛋白类物质,即细菌素,命名为细菌素Y153。理化性质分析表明,细菌素Y153具有较好的热稳定性、酸碱稳定性可被人体内蛋白酶降解的特性。由此对乳酸链球菌所产细菌素Y153有了初步的研究,为开发天然的食品防腐剂奠定理论基础。     

广谱高效抑菌作用乳酸菌的选育

对从自然发酵辣椒中分离出的66株乳酸菌的抑菌特性进行了研究，结果发现66株乳酸菌中仅有28株对指示菌表现出抑菌活性，从这28株中选育出了三株具有广谱、高效抑菌作用乳酸菌，对这三株乳酸菌的抑菌成分进行了研究，最后发现起抑菌作用的物质是细菌素。     

广谱、高效抑菌作用乳酸菌的选育

本对从自然发酵辣椒中分离出的66株乳酸菌的抑菌特性进行了研究，结果发现66株乳酸菌中仅有28株对指示菌表现出抑菌活性，从这28株中选育出了三株具有广谱、高效抑菌作用乳酸菌，对这三株乳酸菌的抑菌成分进行了研究，最后发现起抑菌作用的物质是细菌素。     

产细菌素屎肠球菌的筛选鉴定及其抑菌特性

从采自四川红原的传统发酵酸乳中分离得到308 株疑似乳酸菌,通过96 孔板法初筛和平板打孔法复筛,筛选出1 株具有明显抑菌作用的菌株SC-Y112。通过形态学观察、16S rDNA序列同源性分析和ropA管家基因序列同源性分析结合生理生化实验,鉴定该菌株为屎肠球菌（Enterococcus faecium）。通过排酸及排除H2O2影响后,该菌株的发酵上清液仍具有明显抑菌活性,经蛋白酶处理后,抑菌效果明显消失或下降,说明发酵上清液中的抑菌成分具有蛋白质性质。进一步探究该菌株所产细菌素的生物学特性、遗传稳定性及抑菌特性表明,该细菌素在菌株接种后6 h产生,12 h达到最高;菌株在连续传代86 代内,产细菌素能力较为稳定;细菌素在 pH 3.0～7.0的条件下稳定,在100 ℃处理30 min后仍具有抑菌活性;SC-Y112所产细菌素具有广谱抗菌性,对单核细胞性李斯特菌有明显的抑菌活性。     

泡菜中产细菌素菌株的分离及细菌素性质的初步研究

从四川泡菜中分离得到一株产细菌素的菌株,经形态学、生理生化鉴定等试验,初步鉴定此菌株为乳酸菌。对其所产细菌素做温度、pH、蛋白酶的敏感性试验,实验结果表明,发酵上清液中的抑菌物质对胃蛋白酶、木瓜蛋白酶较敏感,菌株所产细菌素在高温(121℃20min)和酸性条件(pH 3.0～5.0)下均有较强的抑菌活性,可以较好地抑制革兰氏阳性、阴性菌,筛选得到的菌株所产细菌素是一类具有广谱抑菌活性的细菌素。     

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