PDF(Pubmed)
Abstract：
OBJECTIVE: To study the effect of agitation and temperature on biofilm formation (cell aggregates embedded within a self-produced matrix) by pathogenic bacteria isolated from Raw cow milk (RCM).
METHODS: A 40 RCM samples were gathered from eight dairy farms in Riyadh, Saudi Arabia. After bacterial culturing and isolation, gram staining was performed, and all pathogenic, identified using standard criteria established by Food Standards Australia New Zealand (FSANZ), and non-pathogenic bacteria were identified using VITEK-2 and biochemical assays. To evaluate the effects of temperature and agitation on biofilm formation, isolated pathogenic bacteria were incubated for 24 h under the following conditions: 4 °C with no agitation (0 rpm), 15 °C with no agitation, 30 °C with no agitation, 30 °C with 60 rpm agitation, and 30 °C with 120 rpm agitation. Then, biofilms were measured using a crystal violet assay.
RESULTS: Of the eight farm sites, three exhibited non-pathogenic bacterial contamination in their raw milk samples. Of the total of 40 raw milk samples, 15/40 (37.5%; from five farms) were contaminated with pathogenic bacteria. Overall, 346 bacteria were isolated from the 40 samples, with 329/346 (95.1%) considered as non-pathogenic and 17/346 (4.9%) as pathogenic. Most of the isolated pathogenic bacteria exhibited a significant (p < 0.01) increase in biofilm formation when grown at 30 °C compared to 4 °C and when grown with 120 rpm agitation compared to 0 rpm.
CONCLUSIONS: Herein, we highlight the practices of consumers in terms of transporting and storing (temperature and agitation) can significantly impact on the growth of pathogens and biofilm formation in RCM.
METHODS: A 40 RCM samples were gathered from eight dairy farms in Riyadh, Saudi Arabia. After bacterial culturing and isolation, gram staining was performed, and all pathogenic, identified using standard criteria established by Food Standards Australia New Zealand (FSANZ), and non-pathogenic bacteria were identified using VITEK-2 and biochemical assays. To evaluate the effects of temperature and agitation on biofilm formation, isolated pathogenic bacteria were incubated for 24 h under the following conditions: 4 °C with no agitation (0 rpm), 15 °C with no agitation, 30 °C with no agitation, 30 °C with 60 rpm agitation, and 30 °C with 120 rpm agitation. Then, biofilms were measured using a crystal violet assay.
RESULTS: Of the eight farm sites, three exhibited non-pathogenic bacterial contamination in their raw milk samples. Of the total of 40 raw milk samples, 15/40 (37.5%; from five farms) were contaminated with pathogenic bacteria. Overall, 346 bacteria were isolated from the 40 samples, with 329/346 (95.1%) considered as non-pathogenic and 17/346 (4.9%) as pathogenic. Most of the isolated pathogenic bacteria exhibited a significant (p < 0.01) increase in biofilm formation when grown at 30 °C compared to 4 °C and when grown with 120 rpm agitation compared to 0 rpm.
CONCLUSIONS: Herein, we highlight the practices of consumers in terms of transporting and storing (temperature and agitation) can significantly impact on the growth of pathogens and biofilm formation in RCM.
摘要：
目的：研究搅拌和温度对从生牛乳（RCM）中分离出的病原菌形成生物膜（嵌入自产基质中的细胞聚集体）的影响。
方法：从利雅得的八个奶牛场收集了40个RCM样本，沙特阿拉伯。经过细菌培养和分离，进行革兰氏染色，和所有致病的，使用澳大利亚食品标准新西兰（FSANZ）制定的标准标准进行识别，使用VITEK-2和生化测定鉴定非致病菌。为了评估温度和搅拌对生物膜形成的影响，分离的病原菌在以下条件下孵育24小时：4°C，无搅拌（0rpm），15°C，无搅拌，30°C，无搅拌，30°C，60rpm搅拌，和30°C,120rpm搅拌。然后，使用结晶紫测定法测量生物膜。
结果：在八个农场站点中，三人在其原奶样本中显示出非致病性细菌污染。在总共40个原料奶样本中，15/40（37.5％；来自五个农场）被病原菌污染。总的来说,从40个样本中分离出346个细菌,329/346（95.1％）被认为是非致病性的，17/346（4.9％）被认为是致病性的。与4°C相比,当在30°C下生长时和与0rpm相比在120rpm搅拌下生长时,大多数分离的病原菌表现出生物膜形成的显著增加(p<0.01)。
结论：此处，我们强调消费者在运输和储存方面的做法（温度和搅动）可以显着影响RCM中病原体的生长和生物膜的形成。
方法：从利雅得的八个奶牛场收集了40个RCM样本，沙特阿拉伯。经过细菌培养和分离，进行革兰氏染色，和所有致病的，使用澳大利亚食品标准新西兰（FSANZ）制定的标准标准进行识别，使用VITEK-2和生化测定鉴定非致病菌。为了评估温度和搅拌对生物膜形成的影响，分离的病原菌在以下条件下孵育24小时：4°C，无搅拌（0rpm），15°C，无搅拌，30°C，无搅拌，30°C，60rpm搅拌，和30°C,120rpm搅拌。然后，使用结晶紫测定法测量生物膜。
结果：在八个农场站点中，三人在其原奶样本中显示出非致病性细菌污染。在总共40个原料奶样本中，15/40（37.5％；来自五个农场）被病原菌污染。总的来说,从40个样本中分离出346个细菌,329/346（95.1％）被认为是非致病性的，17/346（4.9％）被认为是致病性的。与4°C相比,当在30°C下生长时和与0rpm相比在120rpm搅拌下生长时,大多数分离的病原菌表现出生物膜形成的显著增加(p<0.01)。
结论：此处，我们强调消费者在运输和储存方面的做法（温度和搅动）可以显着影响RCM中病原体的生长和生物膜的形成。
