A modified selective medium (modified Cetrimide Agar, mCA) consisting of 200 μg/mL benzalkonium chloride (BKC) was developed for the isolation of Pseudomonas aeruginosa from raw milk. Initially, a total of 55 isolate...A modified selective medium (modified Cetrimide Agar, mCA) consisting of 200 μg/mL benzalkonium chloride (BKC) was developed for the isolation of Pseudomonas aeruginosa from raw milk. Initially, a total of 55 isolates were obtained from 14 raw milk samples collected from several dairy plants in Ankara, Turkey. Among these isolates, 19 were identified as Pseudomonas aeruginosa, 28 as Pseudomonas fluorescens, 4 as Acinetobacter baumannii, 2 as Enterobacter intermedium, 1 asEnterobacter agglomerans, and 1 as Escherichia coli using Microbact biochemical test kit. BKC was chosen as a selective agent to suppress growth of competitive flora because it is very effective against a wide range of Gram-negative bacteria while P. aeruginosa is resistant. MICs (minimum inhibitory concentration) for BKC were determined by agar dilution method. The concentration of 200 μg/mL BKC inhibited competitive flora, while 90% of P. aeruginosa strains were resistant. When the results of enumeration of P. aeruginosa and other Gram (-) bacteria in Cetrimide Agar (CA) and mCA were compared, it was observed that mCA was more selective than the standard CA in preventing the growth of competitive flora especially of P. fluorescens.展开更多
The Lactococcus diversity in cow and goat raw milk was investigated. To do so, a protocol had to be established for the specific enumeration of lactococci. Eight agar media and one control medium were analysed to comp...The Lactococcus diversity in cow and goat raw milk was investigated. To do so, a protocol had to be established for the specific enumeration of lactococci. Eight agar media and one control medium were analysed to compare their proficiency in evaluating the Lactococcus population in raw milk: M17 Nal, Elliker, modified Elliker, PCA + milk, modified KCA, modified Chalmers, Turner, FSDA. The M17 medium was used as reference. Eighteen pure strains were tested on these media for their selectivity towards lactococci: six Lactococcus species or subspecies, three Leuconostoc, three Enterococcus, two Lactobacillus, one Streptococcus thermophilus, one Pseudomonas fluorescens, one Escherichia coli and one Staphylococcus aureus. All these bacteria were chosen for their regular presence in raw milk. The KCA medium proved to be the most selective towards lactococci, on condition that 1) we discriminated the colonies using the catalase test and 2) we subtracted the Enterococcus population counted on BEA. However, it was not possible to separate the Streptococcus from the Lactococcus colonies on KCA. The “Lactococcus-like” population including these two genera was estimated at a mean level of 3.18 log(cfu)/mL and 4.14 log(cfu)/mL in cow and goat raw milk respectively. This is consistent with the data already published.展开更多
建立了一种快速、简单、准确的牛奶蛋白改性纤维鉴定方法。使用ESI(Electron Spray Ionization)/TOF(Time of Flight)质谱对牛奶蛋白改性纤维胰蛋白酶解肽进行分析,确定了牛奶蛋白改性纤维特征肽段,使用该特征肽段制备得到特异性单克隆...建立了一种快速、简单、准确的牛奶蛋白改性纤维鉴定方法。使用ESI(Electron Spray Ionization)/TOF(Time of Flight)质谱对牛奶蛋白改性纤维胰蛋白酶解肽进行分析,确定了牛奶蛋白改性纤维特征肽段,使用该特征肽段制备得到特异性单克隆抗体;将酪蛋白包被于T线,建立了针对牛奶蛋白改性纤维的免疫层析快速鉴定方法。该方法以7M尿素为提取剂,检出限为氨基酸质量分数为1.00%的牛奶蛋白改性纤维(相当于混纺4.00%牛奶蛋白改性纤维的纱线),检测时间不超过20min(含前处理)。该方法无需使用分析仪器,对常见的纤维没有非特异性识别,纤维的染色不会对检测结果造成干扰。展开更多
文摘A modified selective medium (modified Cetrimide Agar, mCA) consisting of 200 μg/mL benzalkonium chloride (BKC) was developed for the isolation of Pseudomonas aeruginosa from raw milk. Initially, a total of 55 isolates were obtained from 14 raw milk samples collected from several dairy plants in Ankara, Turkey. Among these isolates, 19 were identified as Pseudomonas aeruginosa, 28 as Pseudomonas fluorescens, 4 as Acinetobacter baumannii, 2 as Enterobacter intermedium, 1 asEnterobacter agglomerans, and 1 as Escherichia coli using Microbact biochemical test kit. BKC was chosen as a selective agent to suppress growth of competitive flora because it is very effective against a wide range of Gram-negative bacteria while P. aeruginosa is resistant. MICs (minimum inhibitory concentration) for BKC were determined by agar dilution method. The concentration of 200 μg/mL BKC inhibited competitive flora, while 90% of P. aeruginosa strains were resistant. When the results of enumeration of P. aeruginosa and other Gram (-) bacteria in Cetrimide Agar (CA) and mCA were compared, it was observed that mCA was more selective than the standard CA in preventing the growth of competitive flora especially of P. fluorescens.
基金the RMT(“Réseau Mixte Technologique”)“Fromages de Terroir”the CASDAR project“FloracQ”(Ministère de l’Agriculture et de la Pêche,Chambre d’agriculture du cantal).
文摘The Lactococcus diversity in cow and goat raw milk was investigated. To do so, a protocol had to be established for the specific enumeration of lactococci. Eight agar media and one control medium were analysed to compare their proficiency in evaluating the Lactococcus population in raw milk: M17 Nal, Elliker, modified Elliker, PCA + milk, modified KCA, modified Chalmers, Turner, FSDA. The M17 medium was used as reference. Eighteen pure strains were tested on these media for their selectivity towards lactococci: six Lactococcus species or subspecies, three Leuconostoc, three Enterococcus, two Lactobacillus, one Streptococcus thermophilus, one Pseudomonas fluorescens, one Escherichia coli and one Staphylococcus aureus. All these bacteria were chosen for their regular presence in raw milk. The KCA medium proved to be the most selective towards lactococci, on condition that 1) we discriminated the colonies using the catalase test and 2) we subtracted the Enterococcus population counted on BEA. However, it was not possible to separate the Streptococcus from the Lactococcus colonies on KCA. The “Lactococcus-like” population including these two genera was estimated at a mean level of 3.18 log(cfu)/mL and 4.14 log(cfu)/mL in cow and goat raw milk respectively. This is consistent with the data already published.
文摘建立了一种快速、简单、准确的牛奶蛋白改性纤维鉴定方法。使用ESI(Electron Spray Ionization)/TOF(Time of Flight)质谱对牛奶蛋白改性纤维胰蛋白酶解肽进行分析,确定了牛奶蛋白改性纤维特征肽段,使用该特征肽段制备得到特异性单克隆抗体;将酪蛋白包被于T线,建立了针对牛奶蛋白改性纤维的免疫层析快速鉴定方法。该方法以7M尿素为提取剂,检出限为氨基酸质量分数为1.00%的牛奶蛋白改性纤维(相当于混纺4.00%牛奶蛋白改性纤维的纱线),检测时间不超过20min(含前处理)。该方法无需使用分析仪器,对常见的纤维没有非特异性识别,纤维的染色不会对检测结果造成干扰。
