低温灌肠制品中苦瓜皂甙抑菌模型的建立

用Gompertz方程对低温灌肠制品冷藏期的特定菌生长曲线进行拟合,模拟Ratkowsky方程腐败菌生长动力学温度模型,建立低温灌肠制品中苦瓜皂甙抑菌模型,对苦瓜皂甙抑菌模型进行数学检验。结果表明,修正的Gompertz方程对接种后低温灌肠制品中特定菌生长曲线拟合性较好。通过苦瓜皂甙抑制模型可得大肠杆菌、金黄色葡萄球菌和生孢梭菌可耐受的苦瓜皂甙最高浓度分别为212.735、186.103、170.251mg/kg。抑菌模型经数学检验证明,模型的适用性、准确性和拟合性均在可接受的范围内,有应用价值。     

凉皮中金黄色葡萄球菌生长预测模型的建立

为了研究金黄色葡萄球菌在凉皮中的生长规律,通过测定5℃、10℃、15℃、20℃、25℃下金黄色葡萄球菌在凉皮中的生长数据,采用Baranyi模型、Modified Gompertz和Huang模型拟合金黄色葡萄球菌的生长曲线。比较3种模型的相关系数和参数,将一级模型得到的最大比生长速率(μmax)与迟滞期(λ)建立与温度相关的二级模型。实验表明,Modified Gompertz模型建立的一级模型的偏差因子(B_f)和准确因子(A_f)均在合理范围内。采用Modified Gompertz模型拟合的μmax和λ建立其与温度的平方根模型,拟合得到的R2为0.80和0.88,说明Modified Gompertz模型最适合拟合生长曲线,二级模型经方差分析显示方程显著,表明所建模型能有效预测金黄色葡萄球菌在凉皮中的生长情况。本研究为凉皮中金黄色葡萄球菌的定量风险评估提供理论依据。     

凉皮中金黄色葡萄球菌生长预测模型的

为了研究金黄色葡萄球菌在凉皮中的生长规律,通过测定 5 ℃、10 ℃、15 ℃、20 ℃、25 ℃下金黄色葡萄球菌在凉皮中的生长数据,采用 Baranyi 模型、Modified Gompertz 和 Huang 模型拟合金黄色葡萄球菌的生长曲线。比较 3 种模型的相关系数和参数,将一级模型得到的最大比生长速率（μmax）与迟滞期（λ）建立与温度相关的二级模型。实验表明,Modified Gompertz 模型建立的一级模型的偏差因子（Bf）和准确因子（Af）均在合理范围内。采用 Modified Gompertz 模型拟合的 μmax和 λ 建立其与温度的平方根模型,拟合得到的 R2为 0.80 和 0.88,说明 Modified Gompertz 模型最适合拟合生长曲线,二级模型经方差分析显示方程显著,表明所建模型能有效预测金黄色葡萄球菌在凉皮中的生长情况。本研究为凉皮中金黄色葡萄球菌的定量风险评估提供理论依据。     

金黄色葡萄球菌在菠菜中生长预测模型的建立

目的运用预测食品微生物学的方法研究不同温度下模拟菠菜感染金黄色葡萄球菌的生长规律,选取了4种模型(Gompertz模型、Logistic模型、Richards模型、Linear模型)进行拟合,建立不同温度下的生长模型。方法采用GB4789.10-2010第2法,测定不同温度下金黄色葡萄球菌在菠菜中的生长曲线,并利用CurveExpert 1.3软件将曲线数据分别拟合Gompertz方程、Logistic方程、Richards方程和Linear方程,确定最适方程,建立一级模型和二级生长预测模型。结果通过标准差和相关系数的比较,得出10℃的最适生长模型为Linear模型,15℃、20℃和25℃的最适生长模型为Gompertz模型,再通过不同温度下最适生长模型得到菠菜中金黄色葡萄球菌的生长参数。结论菠菜中金黄色葡萄球菌生长预测模型的建立为菠菜中金黄色葡萄球菌的风险管理部门提供监管依据,也为菠菜制品的安全生产和流通提供了科学依据。     

金黄色葡萄球菌在生乳中生长预测模型的建立

目的建立生乳中金黄色葡萄球菌的生长预测模型。方法采用GB/T4789.37—2008第三法,测定不同温度下金黄色葡萄球菌在生乳中的生长曲线,利用麦夸特法和通用全局优化法将曲线数据分别拟合Gompertz方程、Logistic方程、Richards方程、Weibull方程、Baranyi方程和Monod方程,确定最适方程,建立一级模型。同时应用响应面方程建立二级生长预测模型。结果金黄色葡萄球菌在生乳中的最适预测模型为Gompertz模型。结论通过与多模型比较,建立了金黄色葡萄球菌在生乳中的生长预测模型。为该菌在生乳中的风险评估理论体系的建立提供理论基础,也为乳制品的安全生产和流通提供了科学依据。     

模拟蟹肉中金黄色葡萄球菌生长模型的建立

运用预测食品微生物学的方法研究了不同温度下模拟蟹肉中金黄色葡萄球菌的生长规律,选取了3种模型(Gompertz模型、Logistic模型、Linear模型)进行拟合,建立不同温度下的生长模型。通过标准差和相关系数的比较得出10℃的最适生长模型为Linear模型,15℃、20℃、25℃、30℃的最适生长模型为Gompertz模型,再通过不同温度下最适模型方程得到模拟蟹肉中金黄色葡萄球菌的迟滞期λ、最大生长速率μm以及相对最大细菌浓度(A)。     

冷藏三文鱼片微生物生长动力学模型适用性分析及货架期模型的建立

为研究不同冷藏温度(0,4,10℃)下三文鱼片中菌落总数、明亮发光杆菌、乳酸菌、假单胞菌以及产H2S细菌的生长情况,用不同的微生物生长动力学模型对其微生物生长动态进行非线性拟合,探究动力学模型对冷藏三文鱼片微生物生长的适用性,建立其剩余货架期模型。分别以一级化学反应动力学模型、修正的Gompetz模型、Baranyi and Roberts模型作为一级微生物生长动力学模型,描述微生物在恒定温度下随时间的生长规律;分别以Arrhenius方程和Belehradek方程(平方根模型)为二级模型,描述贮藏温度对微生物生长曲线的最大比生长速率(μmax)及延滞时间(λ)的影响。结果显示:Baranyi and Roberts模型方程能更好地描述冷藏三文鱼片中微生物的生长动态,拟合效果优于一级化学反应动力学模型和修正的Gompertz模型。Baranyi and Roberts模型方程所得参数用Belehradek方程拟合,结果发现冷藏三文鱼片微生物生长的最大比生长速率和延滞时间与贮藏温度呈良好的线性关系。由Belehradek方程建立的冷藏三文鱼片剩余货架期模型相对误差在(±18.90%)内,比Arrhenius方程建立的货架期预测模型预测更准确,可很好地描述菌落总数、假单胞菌、产H2S细菌及明亮发光杆菌随贮藏时间和温度的变化规律,预测冷藏三文鱼片的货架期。     

糯米面团中金黄色葡萄球菌生长预测模型的构建

通过建立一级和二级模型描述糯米面团中金黄色葡萄球菌的生长动力学,为糯米制品原料中金黄色葡萄球菌的生长监测提供依据。将2株金黄色葡萄球菌(ATCC 8095和NCTC 8325)混合菌悬液接种至糯米面团样品中,分别将其在4、11、18、25、32℃和37℃恒温培养。结果表明,除4℃生长缓慢无法构建模型外,其他温度下3种一级生长模型(Baranyi、修正的Gompertz和Huang模型)均能对糯米面团中金黄色葡萄球菌生长曲线进行良好的拟合;但在较低和较高温度(11℃和37℃)下修正的Gompertz模型表现出最好的拟合准确度。赤池信息准则和决定系数(R²)等数据分析显示,修正的Gompertz模型可作为金黄色葡萄球菌最优一级生长预测模型。采用2个二级模型(Ratkowsky和Huang平方根模型)分析温度对金黄色葡萄球菌生长速率的影响,结果表明Ratkowsky平方根模型预测最低(0.049℃)和最高(47.135℃)生长温度相较于Huang平方根模型与实验结果更为接近,因而更适合作为糯米面团中金黄色葡萄球菌的二级生长模型。本研究结果可对食品企业和监管机构预测糯米制...     

冷冻鱼糜中金黄色葡萄球菌生长预测模型的筛选

为建立冷冻鱼糜中金黄色葡萄球菌生长预测模型,将金黄色葡萄球菌接种到冷冻鱼糜制品中,分别采用Gompertz模型、Logistic模型、Richards模型,拟合金黄色葡萄球菌在10,15,20,25℃条件下的生长数据,通过残差分布以及拟合度(RSS、RSE、AIC)等统计指标,分析比较4种模型的拟合能力,建立各温度条件下金黄色葡萄球菌最适一级生长模型。结果表明:10℃条件下Logistic模型拟合的RSS、RSE、AIC值最小,分别是0.742,0.352,-4.458;而Gompertz模型在15,20,25℃条件下拟合的RSS、RSE、AIC值最小,分别是0.403,0.259,-9.961;0.285,0.239,-13.089和0.273,0.234,-13.473。综合比较,10℃条件下,冷冻鱼糜中金黄色葡萄球菌最适一级生长模型为Logistic模型,而15,20,25℃适合采用Gompertz模型。     

金黄色葡萄球菌生物被膜基因型的分子鉴定

本文选用常见的典型食源性微生物金黄色葡萄球菌,从食品微生物安全角度出发,采用生物被膜菌落结晶紫染色法定量检测58株金黄色葡萄球菌菌株生物被膜的形成能力。并对金黄色葡萄球菌生物被膜相关基因型进行分型研究,包括ica调控子分型(ica A、ica D、ica BC)与粘附特性分型(agr、atl E和aap)研究。结果显示,所有检测菌株均能生成生物被膜,其中3株能生成强粘附性生物被膜,占5.2%;生成中等生物被膜能力菌株有23株,占39.7%;32株金黄色葡萄球菌生成弱粘附生物被膜,占55.2%。实验所用的58株菌株中有48株能扩增出ica A基因,56株扩增出ica D基因,57株扩增出ica BC基因,56株扩增出agr,分别有53株和57株染色体中存在aap和atl E基因。本实验的结论:ica操纵子为金黄色葡萄球菌生物被膜形成所必须,aap基因可能作为促进金黄色葡萄球菌生物被膜形成的一个独立因素。而atl E,agr基因是金黄色葡萄球菌生物被膜粘附过程中形成所必须的调节因子。     

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