不同防腐剂对3 种模式腐败菌抑菌效果的比较

目的：研究食品防腐剂对腐败菌的抑菌效果。方法：采用微量稀释法测定不同防腐剂对藤黄微球菌、枯草芽孢杆菌和大肠杆菌的最小抑菌质量浓度(MIC)。结果：对于藤黄微球菌(G+),抑菌效果最好的是乳酸链球菌素(Nisin)与ε- 聚赖氨酸,MIC 均为12.5μg/mL;对于枯草芽孢杆菌(G+),抑菌效果最好的是丙酸钙、丁二酮、柠檬酸、柠檬醛和D- 异抗坏血酸钠,MIC 均为6.25μg/mL;对于大肠杆菌(G －),抑菌效果最好的是过氧化氢和丁二酮,MIC 均为25μg/mL。结论：不同防腐剂对3 种模式腐败菌的抑制效果有所差异,应复配使用。     

花生芽中白藜芦醇粗提物对香肠中4种腐败菌的抑菌活性

目的:研究花生芽中白藜芦醇粗提物对香肠腐败菌的抑制作用,旨在减少香肠中化学防腐剂的使用。方法:从腐败香肠中筛选出腐败菌,用花生芽Res粗提物作用于这些腐败菌,研究其抑菌效果。结果:从腐败香肠中共分离出4种菌,经分离鉴定分别为地衣芽孢杆菌、枯草芽孢杆菌、空气芽孢杆菌和漠海威芽孢杆菌。花生芽粗提物对4种腐败菌都有抑菌效果,其中对地衣芽孢杆菌的抑菌效果最好,当花生芽粗提物的质量浓度为400mg/mL时,对地衣芽孢杆菌的抑菌圈直径达到7.6 mm。花生芽粗提物对4种腐败菌的最低抑菌质量浓度(MIC)分别为200,400,400和200 mg/mL,最低杀菌质量浓度(MBC)均为400 mg/mL。结论:花生芽粗提物可以作为一种抗菌剂以食品添加剂的形式添加到到香肠中。     

高良姜提取物抑菌活性及稳定性研究

采用牛津杯法与二倍梯度稀释法对高良姜提取液抑菌广谱性、最小抑菌浓度(MIC)、最小杀菌浓度(MBC)进行研究,同时与食品常用的防腐剂山梨酸钾、苯甲酸钠的最小抑菌浓度进行比较,并考查高良姜提取液的稳定性。结果表明,提取物对8种菌的抑菌活性依次为:金黄色葡萄球菌蜡样芽孢杆菌副溶血性弧菌苏云金芽孢杆菌枯草芽孢杆菌沙门氏菌希瓦氏菌大肠杆菌。对蜡样芽孢杆菌的MIC为0.012 5mg/mL,对金黄色葡萄球菌的MIC为0.098mg/mL,对大肠杆菌的MIC为1.56 mg/mL,山梨酸钾MIC为2.5mg/mL,苯甲酸钠MIC为25.0 mg/mL。在一定范围内高良姜提取液对pH、盐浓度、糖浓度稳定,对温度、紫外光照不稳定。高良姜提取物具有广泛的抑菌谱,抑菌效果强于山梨酸钾、苯甲酸钠,有望成为新一代绿色防腐剂。     

柠檬酸和氯化钠抑制地衣芽孢杆菌生物被膜的研究

地衣芽孢杆菌是食品中常见腐败菌。该研究发现地衣芽孢杆菌在常见培养基（如TSB、NB、LB、1/2LB）中均有较强的产生物被膜能力,地衣芽孢杆菌稀释100倍、在胰酪胨大豆肉汤（TSB）培养基中30 ℃静置培养更利于地衣芽胞杆菌在96孔板上产生物被膜。测得地衣芽孢杆菌对柠檬酸和氯化钠的最低抑菌质量浓度（MIC）分别为1.28 mg/mL和64 mg/mL。采用结晶紫染色法,研究不同质量浓度柠檬酸和氯化钠对地衣芽孢杆菌生物被膜的抑制效果。结果显示,1/2MIC的氯化钠即能显著抑制地衣芽孢杆菌生物被膜形成（P＜0.01）;而1/2MIC和1MIC的柠檬酸对地衣芽孢杆菌生物被膜形成无明显抑制效果（P＞0.05）。     

防腐剂对地衣芽孢杆菌的抑制效果

通过药敏纸片法、最小抑菌质量浓度(MIC)法测定地衣芽孢杆菌对不同防腐剂的敏感性,利用正交试验设计筛选出最佳的防腐剂组合,并对获得的最佳防腐剂组合的抑菌效果进行验证。结果表明:地衣芽孢杆菌对山梨酸钾、乳酸钠不敏感;对Nisin、ξ-聚赖氨酸和尼泊金乙酯较为敏感,在20mg/mL时其抑菌圈直径分别为9.25、10mm和7.5mm,MIC分别为0.078、0.078mg/mL和2.5mg/mL。正交试验结果表明:当Nisin、ξ-聚赖氨酸和尼泊金乙酯质量浓度分别为0.313、0.313mg/mL和0.125mg/mL时,对地衣芽孢杆菌的抑制效果最佳,可使基质中的地衣芽孢杆菌数(空白样品中为5.48(lg(CFU/g))降低2(lg(CFU/mL))。选择这一最佳组合分别对其在肉制品、乳制品、果汁中的应用效果进行测定,结果显示在0～4℃条件下,复配防腐剂的效果较好。     

解淀粉芽孢杆菌HRH317菌株抗菌肽发酵条件优化及其抑菌活性研究

本文以抑菌圈直径为指标,采用单因素试验和响应面法对解淀粉芽孢杆菌HRH317菌株产抗菌肽的发酵条件进行优化,并对该抗菌肽的抑菌谱及其最小抑菌浓度(MIC)进行了研究。得到最佳发酵条件为：pH7.5,装液量为50 mL,接种量3%,培养时间13h、温度38.5℃、转速145r/min,抗菌肽含量441.56±1.24 μg/mL。在此条件下抗菌肽的抑菌圈直径达15.95 mm。针对9种指示菌的抑菌谱结果表明,抗菌肽对枯草芽孢杆菌、金黄色葡萄球菌抑制效果最好,其次是霉菌、酵母菌。其中,抗菌肽对枯草芽孢杆菌、金黄色葡萄球菌的MIC为 3.45 μg/mL,大肠杆菌、白地霉、巴氏醋酸杆菌MIC为6.9 μg/mL,禾谷镰孢菌、黄曲霉、假丝酵母MIC为 55.20 μg/mL,红酵母MIC为110.40μg/mL。     

南五味子乙醇提取物对食品腐败细菌的抑菌活性研究

目的:研究南五味子乙醇提取物的体外抑菌活性,以期为寻求新的天然食品防腐剂提供实验依据。方法:以抑菌圈直径、最低有效抑菌浓度等为指标,以金黄色葡萄球菌、乙型副伤寒沙门氏菌等7种食品腐败细菌作为供试菌,研究南五味子乙醇提取物的体外抗菌活性。结果:南五味子乙醇提取物对供试菌的抑菌圈直径均>20mm,且对革兰氏阳性细菌的抑制效果强于革兰氏阴性细菌。乙醇提取物对供试菌的MIC值和MBC值分别为金黄色葡萄球菌3.125,6.25mg/mL,蜡样芽孢杆菌1.562,3.125mg/mL,大肠杆菌25,25mg/mL,变形杆菌12.5,25mg/mL,枯草芽孢杆菌、乙型副伤寒沙门氏菌、宋内氏志贺氏菌、铜绿假单胞菌的MIC值和MBC值均为12.5mg/mL。提取物对供试菌的抑菌率随抑菌作用时间的延长,提取物浓度的增加而升高。提取物对蜡样芽孢杆菌抑菌能力大于苯甲酸钠和山梨酸钾;对金黄色葡萄球菌的抑菌能力与苯甲酸钠相同,稍差于山梨酸钾。结论:南五味子乙醇提取物对食品腐败细菌具有显著的抑菌活性,有望开发成天然食品防腐剂。     

桫椤茎中牡荆素的抑菌活性

从体外试验的角度观察牡荆素的抑菌作用。以大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌为供试菌种,采用滤纸片法和试管内药液2倍稀释法测定牡荆素的抑菌圈直径和最低抑菌浓度(Minimal inhibitive concentration,MIC)。牡荆素对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌均有明显的抑制作用,对大肠杆菌的最低抑菌浓度(MIC)为100μg/mL,对金色葡萄球菌的最低抑菌浓度(MIC)为25μg/mL,对枯草芽孢杆菌的最低抑菌浓度(MIC)为100μg/mL。牡荆素具有良好的体外抑菌作用。     

Nα-月桂酰-L-精氨酸乙酯盐酸盐对5种果蔬腐败菌的抑菌活性

通过体外抑菌试验评价N~α-月桂酰-L-精氨酸乙酯盐酸盐(Nα-lauroyl-L-arginate ethylester,LAE)的抑菌活性。以果蔬腐败菌中具有代表性的指状青霉、意大利青霉、灰葡萄孢、链格孢、胡萝卜软腐病坚固杆菌为模式菌,测定LAE对5种腐败菌的最低抑制浓度(Minimum Inhibitory Concentration,MIC),并测定LAE对霉菌的菌丝生长抑制率以及对细菌的杀菌效果。同时探究LAE和其他几种果蔬防腐剂的联合抑菌效果。结果表明:LAE对4种真菌性腐败菌灰葡萄孢、链格孢、意大利青霉、指状青霉的MIC分别为400,200,400,400μg/mL,当LAE浓度达到对各菌的MIC后,能对各霉菌保持较高的菌丝抑制率,分别为100%(16h),78.2%(48h),81.8%(48h),79.1%(48h);LAE对细菌性腐败菌胡萝卜软腐病坚固杆菌的MIC为25μg/mL,且50μg/mL的LAE能在90min内完全杀灭受试菌;LAE与尼泊金甲酯钠共同使用时对模式菌有最佳的联合抑制效果。     

生物抑菌剂对4种常见腐败菌抑制效果

枯草芽孢杆菌、蜡样芽孢杆菌、金黄色葡萄球菌和沙门氏菌是食品中常见的腐败菌。为减少其对食品的污染,研究不同生物抑菌剂对4种腐败菌的MIC、MLC,以及在不同质量浓度、pH和螯合剂作用下的抑菌效果。结果表明:ε-PL对4种腐败菌的MIC均为0.125 g/L,MLC除沙门氏菌为0.2 g/L,其余均为0.125 g/L;Nisin对4种腐败菌的MIC依次分别为0.125、0.25、0.25、0.5g/L;MLC分别为2.5、3.0、2.5、3.0 g/L。CTS对4种菌的MIC除沙门氏菌为0.5 g/L,其余均为0.25g/L,CTS对4种菌的MLC除金黄色葡萄球菌为4.0 g/L,其余均为5.0 g/L。3种生物抑菌剂的抑菌效果随着质量浓度的增大而逐渐增强。ε-PL对革兰氏阳性及阴性菌均具有较好的的抑菌效果,在中性条件下(pH=7)抑菌效果最佳。而Nisin与CTS在酸性条件下(pH=3左右)抑菌活性较高。生物抑菌剂与EDTA复配均有一定的协同增效作用,其中ε-PL与EDTA复配的抑菌效果最佳。     

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.     

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.     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.