大肠菌群与大肠杆菌的比较
定义范围不同，体现特性的差别见表1。
大肠菌群的检测综述
目前食品行业测定大肠菌群方法有国标法（GB）、行标法（SN）和快速检测法（3M）。
三种方法各有特点，其中，国家标准采用三步法：1）乳糖发酵试验：样品稀释后，选择三个稀释度，每个稀释度接种三管乳糖胆盐发酵管。36±1℃培养48±2h，观察是否产气。2）分离培养：将产气发酵管培养物转种于伊红美蓝琼脂平板上，36±1℃培养18h—24h，观察菌落形态。3）证实试验：挑取平板上的可疑菌落，进行革兰氏染色观察。同时接种乳糖发酵管36±1℃培养24±2h，观察产气情况。
检测过程中的注意事项
3.1 取样时的注意事项：
无菌取样时，要针对取样容器的结构、材质和理化性质，选择酒精擦拭、火焰燃烧等适当的灭菌方式进行取样口表面灭菌。
在对容器或管道进行液体无菌取样时，要充分排除和主题基质不一致的前端样品，以确实保证取样的代表性。
发酵试验时的注意事项
4.1 乳糖发酵管做法是大试管中装一支倒立的小试管，然后加入乳糖发酵液9ml—10ml，以超过小试管1cm—2cm为宜。
分离培养时的注意事项：
5.1 结晶紫中性红胆盐琼脂，是大肠菌群固体培养基测定法时用到的，其配制应在使用前临时配制，并放置时间最好不要超过3小时。
防止污染的大措施：
6.0 加强啤酒生产用水环境治理与消毒处理，对于发现问题要立即解决；定期对使用原料、工艺过程、空气、设备工具等进行监控防止污染源进入系统；在设备清洗灭杀之前先使用85℃以上热水清洗并后续以85℃火碱清洁无害。此外对于所有操作人员需接受培训并严格遵守卫生规范以减少人为因素导致的大量污染事件发生概率。
7.Certification Test:
To confirm the presence of E.coli, the bacteria must be isolated from the suspected sample and grown on selective media such as MacConkey agar or Eosin Methylene Blue (EMB) agar.
The colonies obtained should be Gram-stained to identify their morphology and biochemical tests should be performed to confirm their identity.
8.Control measures:
Regularly clean and disinfect all equipment, utensils, and surfaces that come into contact with raw materials or products.
Implement a sanitation program for all personnel involved in food production.
Ensure that all incoming raw materials are inspected for contamination before they enter the processing area.
Maintain proper storage conditions for raw materials and finished products to prevent contamination.
By following these guidelines, breweries can effectively detect and control E.coli in their production processes, ensuring a safe product for consumers while minimizing economic losses due to spoilage or recalls caused by contaminated beer.
9.Conclusion:
E.coli is an important indicator of fecal contamination in brewing environments.
It's crucial to implement strict quality control measures throughout the entire process from raw material selection through packaging.
Regular monitoring of water sources, cleaning schedules, sanitizing procedures will help minimize risk associated with this pathogen.
10.References:
[Reference List]