The purpose of sodium thiosulfate in a microbiological sample bottle is to...

The purpose of sodium thiosulfate in a microbiological sample bottle is to remove chlorine residual that may be present. In water treatment and microbiological testing, chlorine is often used as a disinfectant to kill harmful microorganisms. However, when collecting samples for microbiological analysis, the presence of chlorine can negatively impact the results by killing the very organisms that need to be assessed.

Sodium thiosulfate acts as a neutralizing agent, effectively deactivating chlorine and allowing for a more accurate evaluation of the microbial content in the sample. By adding sodium thiosulfate, any chlorine residual is neutralized, ensuring that the collected sample reflects the natural microbial population without interference from chlorination processes. This is critical for obtaining reliable results in microbiological testing, as it preserves the integrity of the sample.

The other options do not align with the primary function of sodium thiosulfate in this context, as it neither enhances microbial growth, stabilizes pH levels, nor acts as a disinfectant. Instead, its key role is specifically focused on chlorine removal for accurate microbiological analysis.