试管扩散法与国标TTC法检测牛乳中β-内酰胺类抗生素残留

以PCA培养基为基础培养基,Bsc953为指示菌,溴甲酚紫为颜色指示剂,对6种β-内酰胺类抗生素残留的不同浓度乳样进行检测,确定了试管扩散法检测指标,并与国标TTC法进行比较,指出试管扩散法经济省时、简便易行,在检测限、检测时间、检测操作方便程度上较国标TTC法具有很强的优越性,可作为国标TTC法的补充,应用于国内牛乳中β-内酰胺类抗生素残留的检测.     

国标TTC法与AOAC纸片法检测乳中β-内酰胺类抗生素残留对比研究

对乳中抗生素残留的两种微生物检测法进行了比较,确定2种标准方法对6种广谱β-内酰胺类抗生素的检测限,同时指出国标TTC法在检测灵敏度方面的缺陷.建议乳中抗生素残留检测过程中,采用特异性与灵敏度高、经济简便、检测限达到MRLS规定的AOAC纸片法作为国标TTC检测法的补充.     

牛乳中青霉素残留检测技术研究进展

牛乳中青霉素残留问题已引起食品安全管理部门和国际组织的广泛关注。介绍了检测牛乳中青霉素残留的3种方法:微生物检测法,免疫检测法,理化检测法。     

牛乳中β-内酰胺类抗生素残留检测方法的对比研究

对乳中抗生素残留的2种微生物检测法进行了比较,确定2种方法对6种广谱-β内酰胺类抗生素的检测限,同时指出了国标TTC法对6种广谱抗生素均不能检出欧盟法典规定的MRL残留浓度,而AOAO纸片法对其检测限均在MRL浓度范围内,且符合欧盟药典确定的最大残留量限制。建议乳中抗生素残留检测过程中,采用特异性与灵敏度高、经济简便、检测限达到MRLs规定的AOAO纸片法作为国标TTC检测法的补充。     

试管扩散法检测牛乳中青霉素G残留量

以抑菌法为基本原理,用嗜热脂肪芽孢杆菌作为供试菌,在培养基中加入指示剂,根据嗜热脂肪芽孢杆菌在牛乳中生长产酸使指示剂变色现象,确定牛乳中的青霉素G残留量。结果表明,该研究全部检测过程可在4h内完成,试管扩散法检测青霉素G的检测限是4μg/kg。与AOAC规定的标准方法嗜热脂肪芽孢杆菌纸片(BSDA)、国标法(TTC法)相比较,该方法操作简单、灵敏度高、成本低、结果易判断且稳定。     

牛奶中抗生素残留量两种检测方法的比较

采用国标TTC方法、SNAP快速检测法对100份生奶的抗生素残留量进行检测.结果显示:SNAP方法与国标TTC方法测定的结果没有显著性差异,提示上述SNAP快速法、可应用于牛奶中抗生素残留的检测,可以考虑作为国标方法的补充.     

乳酸菌发酵法检测牛乳中抗生素残留

目的建立一种简单、准确的检测牛乳中抗生素残留的方法-乳酸菌发酵法。方法以接种量和温度为变量,优化发酵条件;以青霉素为目标抗生素,建立检测方法;以发酵4 h未凝乳的样品中抗生素最低浓度为检测限,测定本方法对20种抗生素的检测限;对比本方法和GB/T 4789.27方法检测111个商品乳样品中抗生素残留检出率,验证本方法的准确性。结果建立了乳酸菌发酵法检测乳中抗生素残留的具体方法;确定了本方法对8类20种抗生素的检测限,其中4类12种抗生素的检测限低于其在牛乳中的最大残留限量(MRL);本方法和GB/T 4789.27方法检测111个商品乳样品抗生素残留检出率分别为9.0%和11.7%。结论本方法操作简单,结果准确,适合企业及基层检测单位作为初筛方法检测牛乳中的抗生素残留。     

嗜热脂肪芽孢杆菌试管法检测牛乳中β-内酰胺类抗生素残留

采用嗜热脂肪芽孢杆菌试管法对牛乳中6种最为常见的β-内酰胺类抗生素残留进行检测,指出嗜热脂肪芽孢杆菌试管法为半定量检测法,对牛乳中β-内酰胺类抗生素残留具有较好的灵敏性.牛乳中青霉素G、氨苄青霉素、羟氨苄青霉素的检测限为6μg/kg,头孢氨苄的检测限为150μg/kg,苯唑青霉素的检测限为15μg/kg、头孢匹林的检测限为30μg/kg.在检测时间、操作难易程度上较BSDA法具有一定的优越性,可应用于牛乳中β-内酰胺类抗生素残留的检测.     

ECLIPSE50试剂盒法与TTC法检测乳中抗生素残留的比较

采用ECLIPSE50试剂盒法和国标TTC（2,3,5-氯化三苯基四氮唑）法同时对40份来自不同奶站的新鲜奶样进行抗生素残留检测。结果表明,ECLIPSE50试剂盒法阳性率20%,国标TTC法阳性率12.5%。检测结果差异显著。同时指出了TTC法在检测灵敏度方面的缺陷。因此,在乳的抗生素残留检测中,灵敏度高、简便、快速的ECLIPSE50试剂盒法可作为国标TTC法的补充。     

牛乳中抗生素残留及其检测方法的研究进展

文中首先说明了牛乳中抗生素残留危害性 ,其次阐述了牛乳中抗生素残留的原因及残留现状 ,最后介绍了牛乳中抗生素残留检测方法的研究进展。     

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.     

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.     

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.     

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.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.