What does the confirmation phase of the MPN test involve?

The confirmation phase of the Most Probable Number (MPN) test is crucial because it serves to verify the presumptive findings obtained during the initial testing phase. In the MPN test, samples are first analyzed to indicate the possible presence of coliforms or other microorganisms through a series of dilution and incubation steps. The presumptive phase provides initial indications based on growth patterns, but it is essential to confirm these findings before final conclusions are drawn.

During the confirmation phase, further testing, such as additional medium growth, biochemical tests, or other molecular methods, is conducted to unequivocally identify whether the organisms detected are indeed the target pathogens. This phase ultimately ensures that the test results are reliable and accurate, which is essential for public health and safety regarding drinking water quality.