现制饮品中金黄色葡萄球菌耐药及遗传特征研究

目的 探究我国现制饮品中金黄色葡萄球菌抗生素耐药及遗传特征。方法 采用微量肉汤稀释法对金黄色葡萄球菌进行药敏测定,同时提取菌株基因组DNA进行全基因组测序,并使用生物信息学分析流程进行基因组特征数据挖掘。结果 现制饮品中43株金黄色葡萄球菌对10种抗生素的总体耐药率为88.4%,分属9种耐药谱,其中3株为耐甲氧西林金黄色葡萄球菌（Methicillin-resistant Staphylococcus aureus,MRSA）。多重耐药菌（Multidrug resistant,MDR）占比16.3%,主要为含乳现制饮品。耐受7类及以上抗生素金黄色葡萄球菌3株,其中1株为MRSA。全基因测序进化分析表明菌株耐药表型与基因型具有良好的相关性,MRSA及多重耐药株出现明显聚集。43株菌属于16种多位点序列分型（multilocus sequence typing,MLST）,其中MRSA菌株包括1株ST45型和2株ST398型。多重耐药株ST型别为ST5、7、15、59、121和398型。多重耐药MRSA株为ST398型。金葡肠毒素基因整体携带率为34.9%,其中sea为主要基因型。MRSA菌株均不携带毒力基因,多重耐药株肠毒素基因携带率为42.9%。3株主要来自含水果类现制饮品的ST1型菌株同时携带6种肠毒素基因,但其仅对青霉素耐药或为敏感株。结论 我国现制饮品中金黄色葡萄球菌存在MRSA及多重耐药菌,且该类菌株在遗传进化中聚类明显,虽然MRSA菌株致病性相对较弱,然而MDR菌株肠毒素基因的高携带率提示耐药金黄色葡萄球菌的潜在危害不容忽视。因此,应加强现制饮品中金黄色葡萄球菌的耐药监测与防控。     

餐厨废水处理脂肪酶产生菌的鉴定及油脂降解特性研究

对一株产脂肪酶优良菌株SX1-5进行了16SrDNA分子鉴定,初步研究了该菌脂肪酶对不同油脂的降解特性。结果表明:通过16SrDNA测序并构建系统发育树,菌株SX1-5与铜绿假单胞菌序列相似性均达99.9%(1438/1439);脂肪酶对甘油三酯及不饱和脂肪酸酯的水解活性较高;玉米油、橄榄油和大豆油处理24h降解率分别达92.3%、90.6%和90.5%,餐厨废水降解试验中,30℃处理96h,油脂降解率达到65.6%,CODcr去除率达70.2%。     

发酵肉制品中细菌群落结构及其表皮葡萄球菌生物胺相关基因分析

该研究首先利用高通量测序技术对发酵肉制品中细菌群落结构进行分析;然后利用传统培养分离法及双层显色培养基对产生物胺的细菌进行分离筛选,并基于16S rRNA基因序列进行鉴定;最后利用聚合酶链式反应（PCR）对产生物胺细菌的赖氨酸脱羧酶、组氨酸脱羧酶和酪氨酸脱羧酶编码基因ldc、hdc、tdc进行扩增。结果表明,发酵肉制品中细菌主要为厚壁菌门（Firmicutes）的葡萄球菌属（Staphylococcus）。从发酵肉制品中共分离得到52株细菌,其中43株具有产生物胺能力,主要为表皮葡萄球菌（Staphylococcus epidermidis）;产生物胺能力较强的7株表皮葡萄球菌中均含有ldc和hdc基因,部分菌株检测到tdc基因,为评估发酵食品生物胺的潜在危害和快速检测奠定基础。     

金黄色葡萄球菌新型肠毒素sek基因在3 株食品分离菌株中的表达

目的：肠毒素sek基因在临床分离的耐甲氧西林金黄色葡萄球菌菌株中较为流行,研究新型肠毒素sek基因的时序性表达可为食物中毒预防和疾病控制补充新的基础数据。方法：本研究针对实验室保存的食源性金黄色葡萄球菌菌株进行21 种肠毒素基因检测,筛选出3 株含sek基因的菌株SA005、SA008和SAB0,针对3 株菌株进行生长曲线测定,随后在培养不同时间段收集菌体提取RNA,利用实时荧光定量聚合酶链式反应（real time-polymerasechain reaction,real time-PCR）检测肠毒素sek基因在12～120 h的相对表达水平。结果：基因检测结果显示,菌株SA005含有16S、nuc、mecA、seb、sec、sek、sex基因,SA008含有16S、nuc、mecA、sea、sek、sex基因,SAB0含有16S、nuc、sek、sex基因。3 株菌株在胰酪胨大豆肉汤培养基中的生长曲线趋势较相似,18 h左右出现折点,之后细菌进入生长稳定期。3 株菌株的sek基因在12～120 h全程表达,SA005的sek基因在48 h时相对表达量最高,在84 h相对表达量最低;SA008在24 h时的相对表达量最高,在48 h相对表达量最低,在60～120 h表达量相对比较稳定;SAB0在12～120 h之间相对表达量呈现抛物线趋势,在60 h和72 h的表达量相对较高且差异不显著（P＞0.05）。结论：3 株菌株sek表达水平存在明显差异,相同菌株sek基因不同时间点表达也存在差异性,菌株基因背景的影响可能是造成sek基因表达差异性的关键。     

鲊肉粉中乳酸菌和葡萄球菌的筛选及鉴定

从传统发酵鲊肉粉中分离、筛选发酵性能优良的乳酸菌和葡萄球菌,为鲊肉粉接种发酵提供理论依据。按照肉制品发酵菌株的筛选标准,利用形态学特征和16S rDNA序列分析鉴定菌株,筛选出2株乳酸菌A1、C7和2株葡萄球菌S6、S7。结果表明:乳酸菌菌株A1、C7均为植物乳杆菌(Lactobacillus plantarum),能快速产酸,具有较好抑菌特性;葡萄球菌菌株S6为沃氏葡萄球菌(Staphylococcus warneri),S7为巴氏葡萄球菌(Staphylococcus pasteuri),能产蛋白酶和脂肪酶,具有良好的耐盐性和耐亚硝酸盐性,对不同抗生素有不同的敏感性。筛选得到的4株菌株具有良好的发酵特性,乳酸菌和葡萄球菌之间无拮抗作用,复配后用可于鲊肉粉接种发酵。     

内蒙古肉制品中葡萄球菌的筛选及生产性能的研究

通过对内蒙古天然风干肉及肉肠中葡萄球菌的筛选,得到105株球菌。对菌株进行降解蛋白质和脂肪试验,筛选出2株具有降解蛋白质,17株降解脂肪的菌株。将19株菌进行耐6.5%Na Cl、10%Na Cl、耐Na NO2、葡萄糖产气、产H2S、硝酸盐还原、产生物胺等试验,结果表明19株菌中H2O2酶试验均为阳性,5株菌硝酸盐还原酶试验阳性,6株菌分解赖氨酸、5株菌分解酪氨酸产胺试验阳性,4株菌产H2S试验阴性。经以上筛选,得到12株菌性能良好菌株。通过生化鉴定,其中5株菌为木糖葡萄球菌,适合用作肉品发酵剂。     

T-2毒素降解菌株的筛选、鉴定与降解机制分析

为获得高效降解T-2毒素的微生物菌株并探究其降解机制，本研究以T-2毒素为底物从小麦样品中筛选降解微生物并进行鉴定，探究该菌株对T-2毒素的降解特性，利用超高效液相色谱-飞行时间质谱仪分析其代谢产物与降解机制。结果表明，从50份小麦样品中筛选到2株T-2毒素高效降解菌株AFJ-2和AFJ-3，通过形态学观察和16S rDNA序列分析，初步鉴定为短小杆菌属（Curtobacterium sp.）菌株和芽孢杆菌属（Bacillus sp.）菌株。菌株AFJ-2和AFJ-3分别能在7 h和12 h内将5μg/mL T-2毒素完全降解，2株菌的胞内酶均对T-2毒素具有显著降解效果（P<0.05），不存在吸附作用。菌株AFJ-2可将T-2毒素转化为HT-2毒素和T-2三醇，菌株AFJ-3降解T-2毒素产生新茄镰孢菌醇（neosolaniol,NEO），基于降解位点推测，2株菌共同作用于T-2毒素可产生新的产物4-脱乙酰-NEO。研究结果丰富了生物降解T-2毒素的菌种资源库，为T-2毒素降解酶的分离纯化及功能基因的挖掘提供一定参考依据。     

复合除油微生物菌剂的油脂去除特性

为扩大油脂降解的菌种库资源，提高餐厨垃圾中油脂的生物转化效率，作者以所在实验室自行保藏的4株微生物菌株为油脂降解菌，通过等比例复配获得研究用复合除油微生物菌剂，研究了影响菌剂除油效果的因素及组成菌株产脂肪酶的能力。结果表明，复合除油微生物菌剂在温度为25~55 ℃、pH为4~9、盐质量浓度为5~90 g/L、油脂体积分数1%~5%、接种体积分数1%~9%时，均具有一定的除油能力，除油率最高可达84.75%。单一菌株实验结果表明，菌株B501所产脂肪酶的酶活最高，而菌株009所产脂肪酶处于高酶活的持续时间较长，因此除油能力也最强。此外，复合菌剂的除油效果优于单一菌株。     

泡菜中具有胆固醇降解功能益生菌的筛选研究

从泡菜中筛选出6株菌株,对其做生理生化、胆固醇降解、耐胆盐性、耐酸性、抑菌性和抗氧化性实验。经初步判定所筛选菌株D1、D4和D6为链球菌属,D2、D3和D5为明串珠菌属,都具有胆固醇降解性,其中D1菌株降解性最好,其降解率在48 h达到81.57%,D1耐酸能力最强,胆盐耐受性仅次于D2菌株,且对大肠杆菌、金黄色葡萄球菌及枯草芽孢杆菌具有较强的抑制作用,对DPPH自由基清除率达到33.88%,可将其作为发酵剂,为益生菌功能食品开发提供基础。     

腌制牛蒡盐卤中嗜盐菌群组成的研究

为了研究腌制牛蒡盐卤中嗜盐菌群物种组成,采用微生物学方法对腌制牛蒡盐卤进行多次逐级梯度稀释后涂布,最后通过划线纯化菌株;通过革兰氏染色观察细菌形态;经聚合酶链反应（PCR）检测,获得16S rRNA基因序列,进而进行序列比对分析,对菌株进行分子生物学鉴定。结果表明,从腌制牛蒡盐卤中筛选分离获得2株嗜盐细菌菌株,编号为X1和X2,其中X1菌株与腐生葡萄球菌（Staphylococcus saprophyticus）模式菌株的16S rRNA基因序列相似度为99.81%;X2菌株与人葡萄球菌（Staphylococcus hominis）模式菌株的16S rRNA基因序列相似度为100%。腌制牛蒡盐卤中的优势菌株为腐生葡萄球菌（Staphylococcus saprophyticus）和人葡萄球菌（Staphylococcus hominis）。     

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.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

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