What do prepared water sample bottles for bacteriological testing contain?

What do prepared water sample bottles for bacteriological testing contain?

• A. Sodium thiosulfate crystals
• B. A disinfectant
• C. Saline solution
• D. No preservative

Answer: (A)

When collecting water for bacteriological testing, the bottle is prepared with a dechlorinating agent to neutralize residual chlorine. Sodium thiosulfate crystals are used because they quickly react with chlorine, turning off its disinfecting effect. This preserves the bacteria in the sample during transport, so the lab can accurately assess contamination. Without a dechlorinating agent, chlorine would continue to kill bacteria and distort results. A disinfectant in the bottle would contaminate the sample, saline solution wouldn’t neutralize chlorine, and no preservative risks bacterial viability being affected by chlorine or other factors.

When collecting water for bacteriological testing, the bottle is prepared with a dechlorinating agent to neutralize residual chlorine. Sodium thiosulfate crystals are used because they quickly react with chlorine, turning off its disinfecting effect. This preserves the bacteria in the sample during transport, so the lab can accurately assess contamination. Without a dechlorinating agent, chlorine would continue to kill bacteria and distort results. A disinfectant in the bottle would contaminate the sample, saline solution wouldn’t neutralize chlorine, and no preservative risks bacterial viability being affected by chlorine or other factors.