Food-borne diseases are the main public health problem throughout the world. Milk is important component of human diet including fats, proteins, vitamins and minerals. It is a best source of calcium and phosphorus. Di...Food-borne diseases are the main public health problem throughout the world. Milk is important component of human diet including fats, proteins, vitamins and minerals. It is a best source of calcium and phosphorus. Different types of pathogenic bacteria like S. aureus and Salmonella enter in milk and then multiply, after multiplication they become active in causing diseases. These bacteria create serious problems for human health. This study aimed to isolate and identify pathogenic bacteria Staphylococcus aureus and Salmonella from raw milk samples of different cities of Pakistan. Primary screening of raw milk samples was done on the basis of morphological, cultural and biochemical techniques. The final identification was made using 16SrRNA sequence analysis. A total of 200 raw milk samples were collected from different cities of Pakistan. Selective medium xylose lysine deoxycholate agar (XLD) and Mannitol salt agar were used for the identification of Salmonella sp. and S. aureus. Staphylococcus aureus produced yellow colonies with yellow zones on Mannitol salt agar. Staphylococcus aureus exhibited gram-positive character with purple coloration and it was detected as cocci-shaped. Biochemically 91 (45%) samples enhibited Catalase, Coagulase, DNase, Urease, Citrate, fermentation tests positive and indole, oxidase and H2S tests negative with nonmotile character, indicating the presence of Staphylococcus aureus. Salmonella sp. was detected as gram negative rods with pink coloration on gram staining. Biochemically 87 (43%) samples revealed catalase, citrate, H2S and fermentation tests positive while oxidase, DNase, Indole and urease tests negative, indicating the presence of Salmonella sp. in these samples. Of the 200 samples tested, 43% were positive for Salmonella, while 45% samples were contaminated with S. aureus. The 16SrRNA sequence analysis confirmed the results of biochemical and cultural characterization by depicting 99% identity of samples with S. aureus and 98% identity with Salmonella spp. The occurrence of high percentage of these pathogenic bacteria in raw milk may be linked to its contamination at the time of collection, processing, strorage and distribution. This quantitative data could be utilized to better establish the appropriate levels of protection for raw milk, dairy products and processing technologies.展开更多
目的:研究比较杜仲不同炮制品的降压活性。方法:选用雄性自发性高血压大鼠(spontaneously hypertension rat strokeprone,SHR-SP),按血压值高低进行随机区间分组,包括杜仲生品组、杜仲炮制品组、杜仲假炮制品组、硝苯地平组(阳性对照组...目的:研究比较杜仲不同炮制品的降压活性。方法:选用雄性自发性高血压大鼠(spontaneously hypertension rat strokeprone,SHR-SP),按血压值高低进行随机区间分组,包括杜仲生品组、杜仲炮制品组、杜仲假炮制品组、硝苯地平组(阳性对照组)、溶剂组(高血压对照组),n=6;另选10只雄性正常Wistar大鼠作为正常对照组;以给药前后清醒大鼠尾动脉血压、心率、体重为检测指标,分析杜仲各制品的降压活性与特点。结果:1经各组给药前后进行自身比较,SHR-SP高血压对照组血压、心率较自身分别显著升高29.2 mm Hg(P<0.01)、67.7 times·min-1(P<0.05);硝苯地平、杜仲生药、炮制品均具有显著抑制SHR-SP大鼠自身基础血压、心率升高的活性,杜仲假炮制品则无此活性,杜仲生药与炮制品抑制自身基础血压升高的活性要强于硝苯地平;2经给药后各制品组分别与高血压对照组进行组间比较,硝苯地平组、杜仲生药组、炮制品组血压较高血压对照组分别低47(28%)mm Hg、45.1(27%)mm Hg、56.3(34%)mm Hg,P均<0.01;杜仲假炮制品组血压较高血压对照组无显著性差异(P>0.05);杜仲炮制品组心率较高血压对照组低47.6 times·min-1(P<0.05)。结论:杜仲药材生品与炮制品均有显著降压活性,炮制品降压活性略优于生品,但两者无显著性差异,假炮制品则无降压活性;杜仲炮制品还具有显著降低心率活性。展开更多
文摘Food-borne diseases are the main public health problem throughout the world. Milk is important component of human diet including fats, proteins, vitamins and minerals. It is a best source of calcium and phosphorus. Different types of pathogenic bacteria like S. aureus and Salmonella enter in milk and then multiply, after multiplication they become active in causing diseases. These bacteria create serious problems for human health. This study aimed to isolate and identify pathogenic bacteria Staphylococcus aureus and Salmonella from raw milk samples of different cities of Pakistan. Primary screening of raw milk samples was done on the basis of morphological, cultural and biochemical techniques. The final identification was made using 16SrRNA sequence analysis. A total of 200 raw milk samples were collected from different cities of Pakistan. Selective medium xylose lysine deoxycholate agar (XLD) and Mannitol salt agar were used for the identification of Salmonella sp. and S. aureus. Staphylococcus aureus produced yellow colonies with yellow zones on Mannitol salt agar. Staphylococcus aureus exhibited gram-positive character with purple coloration and it was detected as cocci-shaped. Biochemically 91 (45%) samples enhibited Catalase, Coagulase, DNase, Urease, Citrate, fermentation tests positive and indole, oxidase and H2S tests negative with nonmotile character, indicating the presence of Staphylococcus aureus. Salmonella sp. was detected as gram negative rods with pink coloration on gram staining. Biochemically 87 (43%) samples revealed catalase, citrate, H2S and fermentation tests positive while oxidase, DNase, Indole and urease tests negative, indicating the presence of Salmonella sp. in these samples. Of the 200 samples tested, 43% were positive for Salmonella, while 45% samples were contaminated with S. aureus. The 16SrRNA sequence analysis confirmed the results of biochemical and cultural characterization by depicting 99% identity of samples with S. aureus and 98% identity with Salmonella spp. The occurrence of high percentage of these pathogenic bacteria in raw milk may be linked to its contamination at the time of collection, processing, strorage and distribution. This quantitative data could be utilized to better establish the appropriate levels of protection for raw milk, dairy products and processing technologies.
