The biofilm formation on equipment surfaces in dairy manufacturing is a major concern for industry and consumers alike, which may affect the safety and quality of dairy products. In order to identify the bio-contamina...The biofilm formation on equipment surfaces in dairy manufacturing is a major concern for industry and consumers alike, which may affect the safety and quality of dairy products. In order to identify the bio-contamination risk of materials commonly used in dairy manufacturing,</span><span style="font-family:""> </span><span style="font-family:Verdana;">adhesion of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Staphylococcus aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> on glass coated by two kinds of UHT milk (whole milk and skimmed milk) was investigated. It is known that adhesion is mainly governed by surface physicochemical properties, for that,</span><span style="font-family:""> </span><span style="font-family:Verdana;">the effect of milk components on physicochemical properties of glass and bacterial surfaces were exanimated through contact angle measurements. MATLAB software was used to evaluate the ability of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">S.</span></i><i><span style="font-family:""> </span></i><i><span style="font-family:Verdana;">aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><i><span style="font-family:""> </span></i><span style="font-family:Verdana;">adhesion on glass.</span><span style="font-family:""> </span><span style="font-family:Verdana;">The hydrophobic quantitative and electron acceptor characteristics of the glass appear to increase with the presence of fat in milk, while its electron donor property</span><span style="font-family:""> </span><span style="font-family:Verdana;">decreases with this component. The percentage of occupied surface of untreated glass was more important than in treated surfaces for 50% of the strains studied.</span><span style="font-family:""> </span><span style="font-family:Verdana;">As well, the percentage of occupied surface by bacterial strains in untreated glass by skimmed milk is generally more important compared to the whole milk. Therefore, the risk of bio-contamination of untreated glass is more favorable for bacteria cultured in skimmed milk compared to these in whole milk but the bio-contamination risk on covered glass by milk is not milk dependent and is strain dependent.展开更多
This study surveyed 180 samples of ultra high temperature （UHT） milk of four top Chinese dairy brands collected in the 25 cities in China in June 2011, and assessed their contamination with antibiotics, using the EL...This study surveyed 180 samples of ultra high temperature （UHT） milk of four top Chinese dairy brands collected in the 25 cities in China in June 2011, and assessed their contamination with antibiotics, using the ELISA method. The percentages of tetracyclines, sulfonamides, sulfamethazine, and quinolones detected in the samples were 0, 16.7, 40.6, and 100%, respectively. The maximum concentrations of the tetracyclines, sulfonamides, sulfamethazine and quinolones in UHT milk samples were 〈1.5, 26.2, 22.6, and 58.8 μg kg-1, respectively. None of the samples exceeded the maximum residue levels （MRLs） for these four veterinary drugs, according to the regulations set by China, the European Union （EU） and the Codex Alimentarius Commission （CAC）.展开更多
以A和B两份国内不同品牌的成品超高温瞬时灭菌(Ultra High Temperature treated,UHT)牛乳为研究对象,通过基于宏基因组DNA 16Sr RNA基因Vl-V3可变区的高通量测序手段对样品中微生物多样性丰度进行了研究。分类学门水平的微生物群落结构...以A和B两份国内不同品牌的成品超高温瞬时灭菌(Ultra High Temperature treated,UHT)牛乳为研究对象,通过基于宏基因组DNA 16Sr RNA基因Vl-V3可变区的高通量测序手段对样品中微生物多样性丰度进行了研究。分类学门水平的微生物群落结构显示,两份UHT牛乳中的微生物主要隶属于厚壁菌门(Firmicutes),拟杆菌门(Bacteroidetes),变形菌门(Proteobacteria)和放线菌门(Actinobacteria)四个菌门。分类学属水平的微生物群落结构显示,两份UHT牛乳中的微生物多样性丰度存在一定的差异,但差异不显著。本研究虽无法准确定位导致差异的因素,但仍可为后续UHT乳的理论研究及原料乳和UHT牛乳产品处理工艺的提升提供一定的数据基础。同时,该研究也侧面反映宏基因组测序技术在UHT牛乳中微生物多样性的检测方面具有很大的优势,可作为相关实际生产中重要的配套技术进行应用推广。展开更多
文摘The biofilm formation on equipment surfaces in dairy manufacturing is a major concern for industry and consumers alike, which may affect the safety and quality of dairy products. In order to identify the bio-contamination risk of materials commonly used in dairy manufacturing,</span><span style="font-family:""> </span><span style="font-family:Verdana;">adhesion of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Staphylococcus aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> on glass coated by two kinds of UHT milk (whole milk and skimmed milk) was investigated. It is known that adhesion is mainly governed by surface physicochemical properties, for that,</span><span style="font-family:""> </span><span style="font-family:Verdana;">the effect of milk components on physicochemical properties of glass and bacterial surfaces were exanimated through contact angle measurements. MATLAB software was used to evaluate the ability of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">S.</span></i><i><span style="font-family:""> </span></i><i><span style="font-family:Verdana;">aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><i><span style="font-family:""> </span></i><span style="font-family:Verdana;">adhesion on glass.</span><span style="font-family:""> </span><span style="font-family:Verdana;">The hydrophobic quantitative and electron acceptor characteristics of the glass appear to increase with the presence of fat in milk, while its electron donor property</span><span style="font-family:""> </span><span style="font-family:Verdana;">decreases with this component. The percentage of occupied surface of untreated glass was more important than in treated surfaces for 50% of the strains studied.</span><span style="font-family:""> </span><span style="font-family:Verdana;">As well, the percentage of occupied surface by bacterial strains in untreated glass by skimmed milk is generally more important compared to the whole milk. Therefore, the risk of bio-contamination of untreated glass is more favorable for bacteria cultured in skimmed milk compared to these in whole milk but the bio-contamination risk on covered glass by milk is not milk dependent and is strain dependent.
基金funded by the Ministry of Agriculture of China (2013-Z10)Chinese Academy of Agricultural Sciences (2012ZL071)Institute of Animal Science, Chinese Academy of Agricultural Sciences (2013ywf-yb-4)
文摘This study surveyed 180 samples of ultra high temperature （UHT） milk of four top Chinese dairy brands collected in the 25 cities in China in June 2011, and assessed their contamination with antibiotics, using the ELISA method. The percentages of tetracyclines, sulfonamides, sulfamethazine, and quinolones detected in the samples were 0, 16.7, 40.6, and 100%, respectively. The maximum concentrations of the tetracyclines, sulfonamides, sulfamethazine and quinolones in UHT milk samples were 〈1.5, 26.2, 22.6, and 58.8 μg kg-1, respectively. None of the samples exceeded the maximum residue levels （MRLs） for these four veterinary drugs, according to the regulations set by China, the European Union （EU） and the Codex Alimentarius Commission （CAC）.
文摘以A和B两份国内不同品牌的成品超高温瞬时灭菌(Ultra High Temperature treated,UHT)牛乳为研究对象,通过基于宏基因组DNA 16Sr RNA基因Vl-V3可变区的高通量测序手段对样品中微生物多样性丰度进行了研究。分类学门水平的微生物群落结构显示,两份UHT牛乳中的微生物主要隶属于厚壁菌门(Firmicutes),拟杆菌门(Bacteroidetes),变形菌门(Proteobacteria)和放线菌门(Actinobacteria)四个菌门。分类学属水平的微生物群落结构显示,两份UHT牛乳中的微生物多样性丰度存在一定的差异,但差异不显著。本研究虽无法准确定位导致差异的因素,但仍可为后续UHT乳的理论研究及原料乳和UHT牛乳产品处理工艺的提升提供一定的数据基础。同时,该研究也侧面反映宏基因组测序技术在UHT牛乳中微生物多样性的检测方面具有很大的优势,可作为相关实际生产中重要的配套技术进行应用推广。
