Which of these methods helps in detecting the presence of coliform bacteria?

The membrane filtration method is a widely accepted technique for detecting coliform bacteria in water samples. This method involves filtering a water sample through a membrane that traps bacteria, which can then be cultured and analyzed.

In the membrane filtration process, the sample is passed through a filter with a specific pore size that allows water and smaller particles to pass through while capturing microorganisms. After filtration, the membrane is placed on a selective growth medium, which promotes the growth of coliform bacteria, enabling them to form visible colonies. This allows for both the identification and quantification of coliforms present in the water sample.

This method is favored for its effectiveness in processing larger volumes of water, making it suitable for assessing water quality in various contexts, including drinking water, recreational water, and wastewater. It provides a clear and direct means of evaluating bacterial contamination, which is crucial for water safety assessments.

The other methods listed, such as gas chromatography and liquid chromatography, are generally not used for this specific purpose, as they are more suited for analyzing chemical compounds rather than biological organisms. Electric conductivity testing, while useful for assessing certain properties of water, does not directly indicate the presence of coliform bacteria.