保加利亚乳杆菌冻干保护剂的研究

采用正交试验研究了保加利亚乳杆菌在冷冻干燥条件下的最佳保护剂的筛选。结果表明：在所选的冷冻干燥保护剂中,VC影响极显著,脱脂乳和谷氨酸钠影响显著,明胶影响不显著;筛选出最佳复合保护刑组成为脱脂乳10％、VC0．5％、谷氨酸钠0．5％、明胶1．5％。     

Biotin exposure–based immunomagnetic separation coupled with sodium dodecyl sulfate,propidium monoazide,and multiplex real-time PCR for rapid detection of viable Salmonella Typhimurium,Staphylococcus aureus,and Listeria monocytogenes in milk

In this study, we established a rapid and sensitive method for the detection of viable Salmonella Typhimurium, Staphylococcus aureus, and Listeria monocytogenes in milk using biotin-exposure-based immunomagnetic separation (IMS) combined with sodium dodecyl sulfate (SDS), propidium monoazide (PMA), and multiplex real-time PCR (mRT-PCR). We used IMS to lessen the assay time for isolation of target bacteria. We then optimized the coupling conditions and immunomagnetic capture process. The immunoreaction and incubation times for 5 μg of mAb coupled with 500 μg of streptavidin-functionalized magnetic beads using a streptavidin-biotin system were 90 and 30 min, respectively. Treatment with SDS-PMA before mRT-PCR amplification eliminated false-positive outcomes from dead bacteria and identified viable target bacteria with good sensitivity and specificity. The limit of detection of IMS combined with the SDS-PMA-mRT-PCR assay for the detection of viable Salmonella Typhimurium, Staph. aureus, and L. monocytogenes in spiked milk matrix samples was 10 cfu/mL and remained significant even in the appearance of 10⁶ cfu/mL of nontarget bacteria. The entire detection process was able to identify viable bacteria within 9 h. The combination of biotin-exposure-mediated IMS and SDS-PMA-mRT-PCR has potential value for the rapid and sensitive detection of foodborne pathogens.     

精梳棉/负离子粘胶纤维紧密纺细特纱的生产

负离子粘胶纤维强伸度低,纺纱与织造困难,从而阻碍了细特高密高档负离子功能性家纺产品的规模化生产.介绍了紧密纺精梳棉与负离子粘胶混纺细特纱的生产技术要点,包括原料选择、纺纱流程和工艺参数选择以及车间温湿度控制等,成纱各项性能指标可达Uster 2007公报25％水平,满足了市场对于高档负离子功能性家纺面料的规模化生产需求...     

果脯蜜饯中霉菌污染情况及污染菌相调查

对杭州市部分超市随机抽取的10种果脯蜜饯中霉菌污染情况及污染菌相调查显示：10种果脯蜜饯的霉菌总数超标率达100％。污染的霉菌有14个菌属,优势菌群为曲霉属,占总数的62．53％,其次为青霉属,占总数的18．56％。     

纯棉赛络纺纱线的色织产品开发

利用赛络纺纱性能特点进行纯棉色织产品的开发。并通过对赛络纺与传统纺纱织物物理性能的比较,证明生产赛络纺纱产品不但可降低成本。而且织物的某些性能优于传统纺纱产品。     

Selective Detection of Mixed Bacterial Survivors from Fish Fillets after Freezing and Thawing by Ethidium Bromide Monoazide Real-Time PCR

The effect of freezing and thawing on the survival of mixed bacteria from cod fillets was studied using ethidium bromide monoazide (EMA) real-time PCR (EMA Rti-PCR). The permeability of cell membranes, media selection, EMA treatment, addition of glycerol, and the number of freeze-thaw cycles were investigated to discriminate and enumerate viable from dead bacteria following freezing and thawing. Universal primers were used to amplify the sequence of a conserved region of all eubacterial 16S rDNA for EMA Rti‐PCR. Amplification of DNA from frozen-thawed bacterial cells was significantly inhibited by EMA, whereas the DNA without EMA from frozen-thawed cells was readily amplified. Freezing and thawing resulted in damage to the cell membrane resulting in increased EMA uptake as revealed by confocal microscopy. The effect of glycerol on survival of the frozen-thawed cells was determined by plate counts and EMA Rti-PCR. Mixed bacteria from fish fillets suspended in saline containing glycerol (5–20%) resulted in greater survival following freezing and thawing than when bacteria were suspended in saline alone during freezing and thawing. Increasing the number of freeze-thaw cycles resulted in a decrease in the log CFU and an increase in Ct value.     

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)。     

植物乳杆菌最适生长底物解析及高密度培养工艺

为提高植物乳杆菌的增殖浓度,分别测定菌株在添加不同氮源、不同缓冲盐、不同浓度的MnSO₄和不同促生长物质时菌株的生长浓度。结果表明,酵母类氮源是植物乳杆菌的最适氮源,缓冲盐在恒pH培养时对菌株生长无促进作用,锰浓度与最高活菌数呈正相关,在以酵母浸粉为氮源时植物乳杆菌培养不需要添加其他生长因子。进一步优化菌株的最适pH值和碳氮比,基于可耐受渗透压,优化恒pH培养和恒pH自动反馈补料培养基和培养工艺,得到各菌株的最适培养策略。3株菌的最适氮源添加量为40～45 g/L,MnSO₄的最适添加量为0. 25 g/L,最适碳氮比为对数生长期生长速率被抑制时的碳氮消耗比。恒pH 5. 5自动反馈补料培养植物乳杆菌X1,活菌数达到4. 1×10¹⁰CFU/mL;恒pH 5. 5分批培养植物乳杆菌N8,活菌数达到2. 9×10¹⁰CFU/m L;恒pH 6. 0分批培养植物乳杆菌N9,活菌数达到6. 2×10¹⁰CFU/mL。该研究结果的应用将显著提高植物乳杆菌的工业化生产效率。     

乳酸菌基础培养基比较研究

研究了脱脂乳中性蛋白酶的最适酶解条件，并以保加利亚乳杆菌和嗜热链球菌为混合发酵菌种，对MRS、脱脂乳和脱脂乳酶解液3种基础培养基进行了比较研究。结果表明：（1）脱脂乳中性蛋白酶的适宜酶解条件为：加酶量5000U／g蛋白质，在pH=7．0，50℃下酶解2h；（2）脱脂乳酶解液是保加利亚乳杆菌和嗜热链球菌混合菌种较好的基础培养基，其冻干发酵剂的质量和数量均优于脱脂乳培养基。以脱脂乳酶解液为基础培养基制备的冻干发酵剂的活菌数达到3．5×10^11cfu／g，冻干发酵剂的重量是脱脂乳的1．93倍。     

发酵乳杆菌的生长限制性因素分析及高密度培养工艺优化

为提高发酵乳杆菌的增殖浓度,对其高密度发酵培养基成分及培养工艺进行优化以提高其活菌数.结果表明,酵母粉复合大分子肽的蛋白胨是发酵乳杆菌的最适氮源,缓冲盐在恒pH培养时对菌株生长无促进作用,Mn2+和Mg2+均是发酵乳杆菌的限制性微量元素.另外,中性条件下酸根的积累不会对发酵乳杆菌有特异性毒害作用,其生长主要是受到渗透压...