二氧化氯和超声波协同作用对鲜蛋表面消毒效果的研究

研究二氧化氯(ClO2)与超声波协同作用对鲜蛋表面大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌的杀灭效果。二氧化氯浓度为0、30、40、50、60mg/L,单独作用及在59kHz 超声波协同作用下分别处理1、5、10min。结果表明：二氧化氯与超声波协同作用与二氧化氯单独作用相比,处理时间10min,对3 个菌种的杀菌量＞ 4.00(lg(CFU/ml)),二氧化氯浓度从60mg/L 降低为50mg/L;协同作条件下二氧化氯浓度50mg/L,对大肠杆菌、金黄色葡萄球菌的杀菌量＞ 4.00(lg(CFU/ml)),处理时间与单独作用相比从10min 缩短为5min。     

中性电解水对水产品接触的工器具杀菌效果

选取菌悬液浓度约为107CFU/mL致病菌金黄色葡萄球菌(Staphylococcus aureus)、福氏志贺氏菌(Shigella flexneri)、副溶血弧菌(Vibrio parahaemolyticus)、大肠杆菌(Escherichia coli)、鼠伤寒沙门氏菌(Salmonella typhimurium)进行杀菌及工器具消毒实验,考察中性电解水对染菌工器具的杀菌效果。结果显示,在2min内,中性电解水有效氯大于78.6mg/kg时,杀菌率均在98%以上。工器具染菌后,2min内,金黄色葡萄球菌、副溶血弧菌、大肠杆菌三种染菌基本全部被杀死。洗手消毒实验和舒适度调查表明,在30s内,中性电解水可将双手污染的250CFU/mL细菌活菌数量减少至5CFU/mL以下,且无味,对皮肤无刺激性。因此,中性电解水在水产品加工过程中可作为理想的消毒剂。     

如意草生物碱提取及抑菌活性研究

通过采用单因素及正交实验,以如意草中生物碱的光吸收值为指标进行检测,优化如意草生物碱的最佳提取工艺为:以乙醇为溶剂时,乙醇浓度75%,料液比1∶10,超声时间120 min,超声温度40℃。在此条件下,如意草生物碱提取率最高,达到1.656%。此外,研究了如意草生物碱对金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌、沙门氏菌的抑菌活性,实验结果表明:如意草生物碱对四种供试菌种均有明显抑制作用,对金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌、沙门氏菌最低抑菌浓度分别为40、50、40、50μg/m L。     

果汁饮料杀菌工艺的验证

采用微生物挑战试验验证果汁饮料杀菌工序温度控制在(90±2℃),持续10min、15min后杀菌的效果。结果表明,往果汁饮料经(90±2℃)水浴持续杀菌10min和15min后,其对大肠杆菌、金黄色葡萄球菌、酿酒酵母、黑曲霉的杀菌率均大于99.99%,但杀菌后的果汁保存3个月后,(90±2℃)水浴持续杀菌10min的果汁有部分霉菌和酵母计数达到15cfu/m L,而(90±2℃)水浴持续杀菌10min的果汁细菌总数及霉菌和酵母计数均小于10cfu/m L,(90±2℃)水浴持续杀菌15min的杀菌效果良好,用于果汁杀菌安全有效,达到杀菌目的。     

气体二氧化氯对苹果表面细菌杀菌规律研究

本实验研究了气体二氧化氯杀灭金黄色葡萄球菌、大肠杆菌、单核细胞增生李斯特氏菌以及腐生酵母菌四种苹果表面的危险致病菌的杀菌规律.在杀菌时间5min、杀菌温度25℃条件下,金黄色葡萄球菌、大肠杆菌、单核细胞增生李斯特氏菌和腐生酵母菌杀菌达到99.99%的杀菌率,所需的气体二氧化氯的浓度分别为23、21、6和11mg/L.在杀菌气体二氧化氯浓度10mg/L、杀菌温度25℃时,四种菌杀菌时间分别达到7、8、2和6.5min时,杀菌率均超过99.99%.在实验范围内,作用温度对杀菌效果影响不大.     

含肉桂醛猪肉糜中金黄色葡萄球菌热失活模型的建立

研究了添加不同质量分数的肉桂醛(0,0.1%,0.5%和1.0%)后猪肉糜中金黄色葡萄球菌的热失活规律。在肉糜中添加不同浓度的肉桂醛后进行热处理(60～75℃),用选择性培养基进行活细胞计数。结果表明,不同温度条件下,肉桂醛对金黄色葡萄球菌的热失活有明显的促进作用,随着温度和肉桂醛浓度的升高,金黄色葡萄球菌的耐热性逐渐降低。在75℃条件下,肉桂醛使肉糜中金黄色葡萄球菌完全热失活所需的时间从5 min减少到3 min。将试验结果进行动力学模型拟合,多项式拟合作为初级模型,能准确地描述添加肉桂醛后肉糜中金黄色葡萄球菌的热失活规律。在二级模型的拟合中,线性模型具有更高的拟合系数值。通过扫描电镜观察肉桂醛处理条件下金黄色葡萄球菌细胞的形态变化,表明肉桂醛可破坏金黄色葡萄球菌的细胞膜,从而导致胞质泄露而死亡。     

基于多重聚合酶链式反应和表面增强拉曼光谱技术的食源性病原菌检测模型的建立与比较

建立基于多重聚合酶链式反应(polymerase chain reaction,PCR)和表面增强拉曼光谱(surface-enhanced Raman scattering,SERS)的沙门氏菌、大肠杆菌和金黄色葡萄球菌检测模型,优化检测方案,提高食源性病原菌检测效率。以病原菌hil A、uid A和clf A的基因序列设计特异性引物,优化多重PCR反应的扩增条件,检测多重PCR的特异性和灵敏性。通过SERS技术检测3种细菌并确定检测限,对3种病原菌进行主成分分析,然后对2种方法的检测限进行比较。结果显示,建立的多重PCR和SERS技术均可特异性地检测出沙门氏菌、大肠杆菌和金黄色葡萄球菌,三重PCR反应的最低检测限为104CFU/m L,最低检出DNA量为50 pg/μL,而SERS检测沙门氏菌最低检出量为103CFU/m L,大肠杆菌和金黄色葡萄球菌的最低检出量为104CFU/m L。PCA分析的前2个主成分的累积贡献率达93. 8%。与多重PCR相比,研究建立的SERS方法提高了沙门氏菌的检测限,敏感度更高,并且缩短了检测时间,对食品中食源性病原菌的监测起到指导作用。     

曲酸对大肠杆菌和金黄色葡萄球菌的抑制作用研究

为了探讨曲酸对食品中常见污染细菌的抑制效果,采用平板稀释涂布法和圆滤纸片法研究曲酸对大肠杆菌和金黄色葡萄球菌的最低抑菌浓度(MIC)、曲酸抑菌热稳定性以及曲酸与ε-聚赖氨酸复合抑菌效果.实验表明:曲酸对大肠杆菌和金黄色葡萄球菌MIC分别是0.25%、0.40%;曲酸经过80、100、120℃处理30 min后MIC不变:1.0%的曲酸与0.001%的ε-聚赖氨酸复合后对金黄色葡萄球菌抑菌能力增强.结论:曲酸对食品中常见污染细菌具有良好的抑菌效果而且热稳定性好,与ε-聚赖氨酸复合对金黄色葡萄球菌抑菌效果具有协同增效作用.     

响应曲面法优化酸性电解水对鲜切苹果杀菌效果的影响

以微生物减菌率为评价指标,在单因素试验的基础上,采用中心组合设计法,研究NaCl质量浓度、处理温度、处理时间,以及料液比对接种金黄色葡萄球菌、大肠杆菌、沙门氏菌和单增细胞李斯特菌的鲜切苹果杀菌效果的影响。响应面分析结果表明,鲜切苹果减菌工艺最优条件为:NaCl质量浓度4.5 g/L,处理温度25℃,处理时间6.45 min,液料比6∶1(m L/g),在此条件下经处理后细菌总数由1.14×105CFU/g降为9.3×103CFU/g,减菌率可达91.84%。同时,该处理对鲜切苹果的p H值和可溶性固形物影响不大,且能较好地抑制维生素C的降解及其表面的褐变。     

金黄色葡萄球菌肠毒素A、B、C在草莓中 表达的研究

目的研究金黄色葡萄球菌在草莓中生长情况及与3种肠毒素SEA、SEB、SEC产生的相关性。方法将实验菌株进行肠毒素分型确认后,分别制备10~4 CFU/g(高)、10~2CFU/g(低)两个浓度菌液,采用浸泡方式人工污染到草莓上,分别于8℃、25℃下贮存,贮存过程中参照GB 4789对草莓进行金黄色葡萄球菌计数和金黄色葡萄球菌肠毒素(A-C)检测。结果适宜条件下,无论初始污染程度高低,金黄色葡萄球菌都能在草莓上正常生长代谢并产生肠毒素,特别是SEA的产生较SEB和SEC迅速。其中,25℃贮存条件下,金黄色葡萄球菌累计到10~4 CFU/g以上就可从样品中检测到SEA,累计到10~5 CFU/g以上可以检测到SEC,累计到10~7CFU/g以上可以检测到SEB;8℃贮存条件下,48 h内未检测到肠毒素。结论以草莓作为金黄色葡萄球菌培养基质,获得了金黄色葡萄球菌生长及与3种常见肠毒素产生的相关性,对草莓微生物风险评估及相关标准制订具有参考意义。     

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