馒头的微生物指标与安全性

贮存实验证明，馒头的菌落总数超过106cfu／g时出现感官品质劣变；保温贮存馒头。12h内菌落总数在104cfu／g以下，霉菌数不超过60cfu／g：4℃贮存5天馒头感官品质没有变化。菌落总数可以保证在106cfu／g以下；冷馒头复热后菌落数从不超过106cfu／g可以降低到103cfu／g以下。市场馒头检验结果显示。商品馒头菌落总数多在800～5000cfu／g之间，过严的要求企业难以实现。     

湿米粉在存放过程中的品质变化

研究了湿米粉在存放过程中感观品质、理化指标以及微生物与卫生指标的变化.结果显示,湿米粉存放在28℃,RH 24%下,存放16 h后,菌落总数达到5.4×105cfu/g,超过标准要求(菌落总数≤3.0×104 cfu/g),熟断条率达到15.4%,超过湿米粉理化指标要求(熟断条率≤15%);存放24 h后,水分含量有所下降,酸度略有增加,感官指标发生显著劣变.     

酱牛肉中腐败细菌的分离与鉴定

本文研究了非真空包装的酱牛肉在0～4℃条件下贮存时细菌总数的变化,并对酱牛肉中主要的腐败细菌进行了分离与鉴定.研究表明,当初始菌数达到103cfu/g时,细菌总数可在3～5d内达到106cfu/g.导致酱牛肉腐败的主要细菌包括葡萄球菌属、肠杆菌科及热死环丝茵,假单胞菌所占比例较小.     

微波杀菌延长羊肉火腿货架期的研究

以羊肉火腿为例,研究了微波加热杀菌的保鲜效果.结果表明:微波80s、100s、120s(功率900W)三种方式以微波1 20s效果最好.可使羊肉火腿的货架期冷藏达三个月.其中第三个月细菌总数为3.89cfu/g,pH为5.71,感官评分9.0.同时通过试验看出,真空包装后的肉品,随着贮存时间的延长,厌氧菌逐渐成为优势菌.到贮存后期,厌氧条件下培养的菌落总数甚至超过有氧条件下培养的菌落总数.故在评价真空包装肉品的卫生质量时,除了考虑国标规定的有氧条件下培养的细菌总数以外,还需考虑厌氧菌数.     

蟹糊微生物控制方法的探讨

采用臭氧、白酒和辐照3种方法对蟹糊原料、半成品及成品进行杀菌处理,以实现蟹糊加工和储运过程中对微生物的控制. 结果表明:用臭氧(质量浓度6mg/L)浸泡蟹糊原料12min,其原始菌落总教由4.86×105cfu/g降至3 500cfu/g,达到国家标准GB10136-2005.白酒对蟹糊的抑菌试验表明:浸泡时间对试验结果的影响极显著(FB=**21.16),其次为白酒浓度(FA=5.35),浸泡温度(Fc=0.76)最不显著.白酒杀菌优方案为A3B3C1,原料菌落总数从1.2×105cfu/g降至864 cfu/g.辐照对蟹糊产品的抑菌试验表明:2、4、6、8 kGy剂量的辐照处理,原始菌落数由2.09×104分别降为213、56、23、7cfu/g;辐照过的产品在贮存期内菌落总数有上升趋势,低温贮藏有利于抑制产品菌落总数上升.     

ε-聚赖氨酸复合生物防腐剂对广式腊肠的防腐效果研究

研究比较以ε-聚赖氨酸、乳酸链球菌素、纳他霉素复配的生物防腐剂以及各单体物质在广式腊肠中的防腐效果,在设定的时间点,参照国标GB789.2-2008方法检测菌落总数,采用半微量定氮法检测挥发性盐基氮含量(TVB-N值).结果表明,在各检测时间点,样品菌落总数及TVB-N值均比对照低,尤其复合防腐剂添加量为0.5g/kg时效果明显,在检测的最后时间点(第30天),菌落总数为104cfu/g,TVB-N值为17.56mg/100g,远低于国家规定的二级鲜肉标准(TVB-N值均低于25 mg/100g),而此时对照菌落总数为106cfu/g,TVB-N值为27.34 mg/100g.     

市售羊肉微生物状况调查

以超市的冷鲜羊肉和农贸市场的热鲜羊肉为研究对象,对其微生物污染状况进行了实地抽查,并对其菌落总数进行了检测和分析。结果表明:(1)不同取样地点羊肉微生物污染状况有显著性差异,超市冷鲜羊肉的菌落总数明显高于农贸市场热鲜羊肉菌落总数;(2)在12处取样地点中,76.36%的羊肉菌落总数分布在7.6×104j1.43×106cfu/g,26.36%的羊肉微生物污染极其严重,超过国家标准(GB184060.3)。     

温度对盐水鹅微生物菌系和品质的影响

对扬州盐水鹅在不同保藏温度下菌落总数、菌相和ph值的变化进行了试验性观察。结果表明,当菌落总数达到106cfu/g、腿肌ph值为6.5以上时,均有异味产生。腐败过程中的优势菌种,37℃为肠球菌属和葡萄球菌属、20℃为变形杆菌属、4℃为假单胞菌属。对于当天制作并于中午出售的盐水鹅,其保藏期限建议值为:37℃不超过7h,20℃不超过24h,4℃不超过6d。建议建立盐水鹅的专项卫生标准。     

低盐虾酱在不同温度下贮藏的品质变化与货架期

对低盐虾酱在20℃、25℃、30℃、35℃下贮藏的品质变化与货架期进行了研究。通过检测贮藏期间菌落总数、副溶血性弧菌、挥发性盐基氮(TVB-N)的变化,并结合感官品质的变化,初步推测了在不同温度下贮藏产品的货架期,并对货架期终点的指标值进行了分析。结果表明:在20℃、25℃、30℃、35℃贮藏过程中,低盐虾酱货架期分别为100d、100d、80d、60d。各温度货架期终点时的菌落总数分别为3.8×104cfu/g、3.9×104cfu/g、4.1×104cfu/g、4.2×104cfu/g,TVB-N值分别为134.6mg/100g,146.8mg/100g,148.7mg/100g,153.6mg/100g,未检出副溶血性弧菌。在4种温度贮藏条件下,感官品质的变化主要是由微生物和化学变化导致的,其变化与菌落总数、TVB-N的变化趋势基本一致。     

响应面法优化泥螺微生物抑制条件

利用SAS中响应面分析方法,对茶多酚等防腐剂在泥螺中微生物抑制作用进行研究,以菌落总数为响应值作响应面和等高线图。结果表明,初始菌数为450cfu/g的泥螺,添加茶多酚等防腐剂后,放置于5±1℃下贮藏,9d后观察,经过优化后,抑制其菌落总数的最佳条件为0.36%的茶多酚,0.028%的乳酸链球菌素和0.03%的溶菌酶,此时菌落总数最小值约为530cfu/g。并对优化条件做验证试验,得到同样条件下菌落总数为560cfu/g,与预测值接近,表明模型拟合度好。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press