What must be included in a sample bottle for bacteriological testing?

In bacteriological testing, it is crucial to ensure that chlorine or any other disinfectants present in the water sample do not interfere with the analysis. Sodium thiosulfate is included in the sample bottle for this purpose. It acts as a dechlorinating agent, neutralizing chlorine and ensuring that the bacteria present in the sample can be accurately measured. The presence of chlorine could kill the bacteria in the sample before analysis, leading to false results that could suggest the absence of harmful microorganisms when they may actually be present.

Including sodium thiosulfate allows for accurate bacteriological assessments by preserving the integrity of the microbiological organisms that need to be identified and counted during testing. This ensures that water quality professionals can make informed decisions about the safety and potability of the water supply.