Long‐term oropharyngeal colonization by C. albicans in children with cystic fibrosis

This longitudinal prospective study aimed to determine the prevalence of oropharyngeal colonization by C. albicans in children with cystic fibrosis (CF), and observe the continuity of candidal colonization and the changes in production of virulence factors, susceptibility to antifungal agents and RAPD patterns of the isolates. Thirty‐seven children with CF were followed‐up for oropharyngeal C. albicans colonization for 18 months. The colonization rate was detected in 54%. All isolates were susceptible to amphotericin B, but those isolated from one patient were resistant to fluconazole. Biofilm production, secretory acid proteinase, phospholipase and esterase activity rates were 30%, 60%, 75% and 80%, respectively. RAPD analysis with the primers OPE‐03 and OPE‐18 was performed for genotyping. RAPD patterns of the strains isolated from the same patient were related to each other, whereas they were not related with other strains isolated from different patients. Two C. albicans strains isolated from the same patient were found to be unrelated to one another. As a result, long‐lasting colonization of the oropharyngeal mucosa of children with CF by endogenous C. albicans isolates having the same RAPD pattern was demonstrated. Colonization prevalance and development of resistance to antifungal agents and the increased production of virulence factors were not correlated. Copyright © 2013 John Wiley & Sons, Ltd.     

去骨凤爪凝胶特性影响因素的研究

以市售凤爪为原料,建立凤爪凝胶特性的综合评价指标,研究压力、pH、氯化钠添加量和柠檬酸钙添加量对去骨凤爪凝胶强度、弹性、脆度和持水率的影响。试验结果表明：四个单因素均能显著提高凤爪的凝胶性能。各因素对去骨凤爪凝胶特性综合指标影响的主次顺序为：氯化钠添加量〉柠檬酸钙添加量〉压力〉pH。由正交试验结果表明去骨凤爪凝胶特性最佳的组合为：500MPa压力下保压25min、pH4.0、氯化钠添加量为1.0%,柠檬酸钙添加量为0.04%。在此组合下,去骨凤爪凝胶特性最好,综合指标为94.765。     

人造板表面耐磨性能测定影响因素的研究与建议

通过不同的试验方法，对影响人造板标准中表面耐磨性能测定结果的因素进行研究，并据此提出对标准改进方面的建议。     

环境因素对屎肠球菌产酪胺的影响

酪胺是发酵食品中广泛存在的、毒性较强的一种生物胺。屎肠球菌作为发酵剂或污染菌广泛存在于发酵食品中,大多数具有产生酪胺的能力,成为发酵食品的潜在安全隐患。该研究以一株黄酒酒曲中分离的产酪胺屎肠球菌为对象,选取葡萄糖、酪氨酸、温度、pH值和酒精含量5个因素,研究这些因素对该菌生长和酪胺合成的影响。结果表明,葡萄糖或酪氨酸添加量对菌体的生长影响不大,温度、环境pH值和酒精含量对菌体生长的影响较显著。酪氨酸对菌体产酪胺促进作用明显,温度＜20 ℃,环境pH值＞5,酒精含量＞10%vol时都会减少酪胺的产生。     

Physiological adaptation of Escherichia coli after transfer onto refrigerated ground meat and other solid matrices: A molecular approach

Bacteria on meat are subjected to specific living conditions that differ drastically from typical laboratory procedures in synthetic media. This study was undertaken to determine the behavior of bacteria when transferred from a rich-liquid medium to solid matrices, as is the case during microbial process validation. Escherichia coli cultured in Brain-Heart Infusion (BHI) broth to different growth phases were inoculated in ground beef (GB) and stored at 5°C for 12 days or spread onto BHI agar and cooked meat medium (CMM), and incubated at 37°C for several hours. We monitored cell densities and the expression of σ factors and genes under their control over time. The initial growth phase of the inoculum influenced growth resumption after transfer onto BHI agar and CMM. Whatever the solid matrix, bacteria adapted to their new environment and did not perceive stress immediately after inoculation. During this period, the σ(E) and σ(H) regulons were not activated and rpoD mRNA levels adjusted quickly. The rpoS and gadA mRNA levels did not increase after inoculation on solid surfaces and displayed normal growth-dependent modifications. After transfer onto GB, dnaK and groEL gene expression was affected more by the low temperature than by the composition of a meat environment.     

北京市城镇居民品牌鸡蛋消费的影响因素分析

在消费需求理论和消费行为理论的基础上,应用统计分析和计量分析方法,实证分析了影响北京市城镇居民品牌鸡蛋消费的主要因素。研究结果表明,居民品牌鸡蛋的消费量受到鸡蛋自身价格、收入、年龄、地域等因素的影响。     

采后因素对果蔬产品营养和质量安全的影响研究现状

果蔬产品是人类日常生活的必需品,事关人类的营养和健康安全。各种采后因素对果蔬产品的营养和质量安全有很大影响。文章系统地总结了果蔬内在因素、微生物、贮藏保鲜方式、包装和运输等各种因子对果蔬产品营养和质量安全的影响,旨在为今后的相关研究提供参考。      

Effects of yoghurt butter oils on rat plasma lipids,haematology and liver histology parameters in a 150‐day study

Although yoghurt butter oil as a fermented dairy product is widely consumed in several countries, its metabolic effects have not been fully elucidated. In this study, male Wistar rats were treated with standard diet, standard diet enriched with 10% or 20% (W/W) of either cow yoghurt butter oil (CYBO), sheep yoghurt butter oil (SYBO) or cottonseed oil (COT) for 20 weeks. Treatment of rats with CYBO or SYBO (at both concentrations) did not significantly influence haematological parameters, plasma lipids and liver histological structure. However, in contrast to popular belief, COT treatment at the higher dose induced leukocytosis, dyslipidaemia and liver steatosis.     

应用Illumina高通量测序技术分析3 种酒曲中微生物多样性

为了解贵州花溪（酒曲A）、盘州（酒曲B）、安顺（酒曲C）3 个地区的酒曲中微生物群落组成和多样性,运用高通量测序技术对酒曲中的细菌16S rDNA V3-V4区和真菌ITS1区进行测序,比较不同地区酒曲中微生物群落结构差异。测定不同地区酒曲的基本理化指标,与酒曲主要细菌种群进行相关性分析。结果显示,细菌获得129 510 条有效序列,1 030 个OTU;真菌获得60 945 条有效序列,19 个OTU。细菌的多样性分析表明,酒曲B中Shannon指数明显低于酒曲A和酒曲C,酒曲A和酒曲C的细菌群落结构更为接近。真菌的多样性分析表明,酒曲C中Shannon指数明显低于酒曲A和酒曲B,酒曲A和酒曲B的真菌群落结构更为接近。在门水平上,酒曲A的优势细菌门为变形菌门（Proteobacteria）,优势真菌门为接合菌门（Zygomycota）;酒曲B的优势细菌门为厚壁菌门（Firmicutes）,优势真菌门为接合菌门;酒曲C的优势细菌门为变形菌门（Proteobacteria）,优势真菌门为子囊菌门（Ascomycota）。在属水平上,酒曲A优势细菌属为红球菌属（Rhodococcus）,酒曲C和酒曲B的优势细菌属均为芽孢杆菌属（Bacillus）;酒曲A和酒曲B的优势真菌属为米根霉属（Rhizopus）,而酒曲C的优势真菌属为酵母属（Saccharomyces）。不同地方来源的酒曲中的微生物组成及多样性在属和门水平上有明显差异;酒曲理化指标与酒曲细菌种群结构具有一定相关性。     

Bacteriocins as food preservatives: Challenges and emerging horizons

ABSTRACT

The increasing demand for fresh-like food products and the potential health hazards of chemically preserved and processed food products have led to the advent of alternative technologies for the preservation and maintenance of the freshness of the food products. One such preservation strategy is the usage of bacteriocins or bacteriocins producing starter cultures for the preservation of the intended food matrixes. Bacteriocins are ribosomally synthesized smaller polypeptide molecules that exert antagonistic activity against closely related and unrelated group of bacteria. This review is aimed at bringing to lime light the various class of bacteriocins mainly from gram positive bacteria. The desirable characteristics of the bacteriocins which earn them a place in food preservation technology, the success story of the same in various food systems, the various challenges and the strategies employed to put them to work efficiently in various food systems has been discussed in this review. From the industrial point of view various aspects like the improvement of the producer strains, downstream processing and purification of the bacteriocins and recent trends in engineered bacteriocins has also been briefly discussed in this review.