Social & Preventive Medicine All the following statements about purification of water are true except A Coliforms must not be detectable in any 100 ml sample of drinking water B Presence of clostridial spores indicate recent contamination C Sodium thiosulphate is used to neutralize chlorine D Coliforms may be detected by multiple tube method and indole production at 44 degrees 💡 Explanation All the following statements about purification of water are true except ✓ Correct Answer: B. Presence of clostridial spores indicate recent contamination