What is the common method for determining the coliform bacteria levels in water?

The membrane filtration method is widely recognized for determining coliform bacteria levels in water. This technique involves filtering a specific volume of water through a membrane filter that captures bacteria. The filter is then placed on a selective agar medium that supports the growth of coliforms while inhibiting other microorganisms. After incubation, colonies that develop can be counted and analyzed for confirmation of coliform presence.

This method is particularly effective because it allows for the analysis of larger water volumes, enhancing the likelihood of detecting low concentrations of coliform bacteria. It also provides a clear and quantifiable means of assessing water quality based on the number of coliform colonies formed. The specificity and efficiency of this technique make it a preferred choice in many water quality testing scenarios.

Other methods, while useful in certain contexts, do not provide the same level of precision or ability to handle various sample volumes as the membrane filtration method.