PA Broth is recommended for the detection of presence & absence of coliform bacteria in water from treatment plants or distribution systems. The Presence Absence (PA) test for the coliform group is a simple modification of the multiple-tube procedures and provides a qualitative estimate of coliforms as per APHA. This test is intended for use on routine samples collected from distribution system or water treatment plants. When PA test is positive, coliform densities can be determined quantitatively in repeat samples to indicate the magnitude of the contamination. PA test is only a presumptive test for the presence of coliforms. Confirmation of these results must be achieved by using a medium like Brilliant Green Bile Broth.
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