Reduction of Escherichia coli O157:H7 and Salmonella enteritidis on mung bean seeds and sprouts by slightly acidic electrolyzed water

High microbial populations on mung beans and its sprouts are the primary reason of a short shelf life of these products, and potentially present pathogens may cause human illness outbreak. The efficiency for inactivating Escherichia coli O157:H7 (E. coli O157:H7) and Salmonella enteritidis (S. enteritidis), which were artificially inoculated on mung bean seeds and sprouts, by means of slightly acidic electrolyzed water (SAEW, pH 5.0 to 6.5) generated through electrolysis of a mixture of NaCl and hydrochloric acid solution in a non-membrane electrolytic chamber, was evaluated at the different available chlorine concentrations (ACCs, 20–120 mg/l) and treatment time (3–15 min), respectively. The effect of SAEW treatment on the viability of seeds was also determined. Results indicate that the ACC had more significant effect on the bactericidal activity of SAEW for reducing both pathogens on the seeds and sprouts compared to treatment time (P < 0.05). The seeds and sprouts treated with SAEW at ACCs of 20 and 80 mg/l resulted in a reduction of 1.32–1.78 log₁₀ CFU/g and 3.32–4.24 log₁₀ CFU/g for E. coli, while 1.27–1.76 log₁₀ CFU/g and 3.12–4.19 log₁₀ CFU/g for S. enteritidis, respectively. The germination percentage of mung bean seeds was not significantly affected by the treatment of SAEW at an ACC of 20 mg/l for less than 10 min (P > 0.05). The finding of this study implies that SAEW with a near-neutral pH value and low available chlorine is an effective method to reduce foodborne pathogens on seeds and sprouts with less effects on the viability of seeds.     

乳品中食源性致病菌快速检测技术研究进展

近年来食源性疾病事件频发,食源性疾病已成为全球化的公共卫生问题,其中有害微生物污染占了较大比重,而乳品因营养丰富可以为众多微生物提供生长所需的营养物质易被其污染。传统的微生物检测方法虽然设备简单、成本低廉,但普遍检测周期长、操作繁琐,对人员操作水平和检验经验要求高。本文综述了分子生物学技术、免疫学技术、光谱技术、基质辅助激光解吸电离飞行时间质谱技术、生物传感器技术以及流式细胞技术在乳品食源性致病菌快速检测的研究进展,展望了乳品中食源性致病菌检测技术向在线化、便捷化、高效化发展前景,以期为后续研究提供参考和借鉴。     

替加环素临床耐药性的研究进展

替加环素作为新一代四环素类抗生素,被用于治疗成人复杂性腹腔内感染和复杂性皮肤及软组织感染。随着临床的广泛使用,替加环素耐药性也屡见报道,或影响其临床疗效。本文对替加环素临床耐药性的研究进展,包括药理作用、临床应用、耐药性的发展以及可能的耐药机制进行综述。     

Fat crystals and emulsion stability — a review

The effects of fat crystals in food emulsion formation and stability are reviewed. Topics discussed in detail include fat crystal wettability, interfacial rheology, crystal microstructure, and particle location. Specifics on the potential future direction of the field are discussed.     

The effects of changes to the post-socialist urban planning framework on public open spaces in multi-story housing areas: A view from Nis,Serbia

This study considers how changes to the post-socialist urban planning framework have affected the treatment of public open space in the transformation of existing mass-housing areas and newly developed multi-story housing areas for the city of Nis, Serbia. The study focuses on quantitative and qualitative changes as well as the physical characteristics of public open spaces, evaluating environmental comfort, safety, accessibility, privacy and intensity of social interactions. The investigation is based on a comparative analysis of three case studies in Nis, which are representative of different developmental, institutional and planning periods. The research indicates a regressive approach in the planning for and treatment of public open space. It also suggests that within the limited economic capacity of local authorities, investors and buyers, the market-oriented post-socialist urban planning framework can lead to spatial and functional fragmentation in housing areas and the degradation or disappearance of not only the public spaces but of open spaces in general.     

Technological properties of Lactobacillus plantarum strains isolated from Chinese traditional low salt fermented whole fish

A total of 21 Lactobacillus plantarum were isolated from a Chinese traditional low salt fermented whole fish product “Suan yu” and identified by biochemical and molecular methods. The isolates were screened for acidifying and amino-biogenic ability for proteolysis, lipolysis, antimicrobial activity, and sensory in order to select the most suitable candidates as the starter cultures. All the strains had high acidifying activities and were able to reduce the pH to lower than 4.5 in 36, 24 and 16 h at 15, 25 and 37 °C respectively. Major strains showed antimicrobial activities against Listeria monocytogenes, Staphylococcus aureus and Escherichia coli, and ten L. plantarum strains could produce bacteriocins. Five L. plantarum strains exhibited weak proteolytic activities against myofibrillar proteins, as evidenced by the agar plate assay and sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE). None of the strains showed lipolytic activity. Major L. plantarum strains displayed different enzymatic profiles. Besides, the isolates mostly showed negative-decarboxylase activities, but Lp-10 had a decarboxylase activity against l-tyrosine. Furthermore, the fermented fish surimi inoculated with Lp-15 and Lp-21 strains respectively scored high for overall acceptability. Therefore, Lp-15 and Lp-21 presented the best technological properties, which should be given first priority as the starter culture for manufacturing fermented fish products.     

Operational characteristics of a marmem device

A reciprocating marmen engine has been devised and built. Examination of stills from cine films of the engine executing its piston-like action have enabled measurements to be made of the times for heat transfer into, and from, the working elements.     

公共引物介导的多重定量PCR技术在转基因大豆检测中的应用研究

目的 建立公共引物介导的多重定量PCR法检测我国农业农村部允许进口的6种转基因大豆(包括: MON87701、DP356043、CV-127、MON87769、MON87705、MON87708)的方法。方法 设计并筛选出针对本研究涉及的6种转基因大豆对特异性引物, 在每对特异性引物的5’端均加上一段公共引物, 形成特异性嵌合引物。以某种转基因大豆DNA为模板, 加入多引物体系以及荧光公共引物验证GeXP(gene expression platform)多重检测体系的特异性, 每种转基因大豆DNA模板浓度分别稀释为20、2、1、0.2、0.02 ng/μL, 运用GeXP多重PCR方法进行单一DNA模板灵敏度分析并优化各对特异性嵌合引物的工作浓度。结果 多重PCR检测体系扩增出特异性片段, GeXP检出的各转基因大豆片段长度MON87701、DP356043、CV-127、MON87769、MON87705和MON87708分别为140.75、184.42、274.93、308.47、467.98和517.67 bp, GeXP 多重检测体系检测敏感性可达到为1 ng/μL, 扩增产物测序结果进一步说明了引物扩增的特异性。结论 本研究建立的基于GeXP系统的多重PCR定量检测技术, 可以准确鉴别6种转基因大豆, 为转基因大豆及其他转基因产品提供了新型的检测方法。     

农贸市场快检实验室运行机制研究

《食用农产品市场销售质量安全监督管理办法》实施以来, 各地市场监管部门要求和鼓励农贸市场建立食品快检实验室, 及时发现和消除食用农产品安全隐患。但目前快检实验室的实际运行状况并不尽如人意, 农贸市场快检实验室运行中存在实验室技术能力薄弱、管理水平低、运行经费不足、检验人员业务素质低、阳性结果后续确证和处置不畅、监督效果不理想等问题。本文重点从技术保障、强化考评、奖扶结合、人员培训、检验联动、监督问责6个方面探讨快检实验室运行机制, 以期解决存在的问题, 促进快检工作的顺利开展, 保障人民群众舌尖上的安全。