Which of the following is a bacteriological indicator of water quality?: (A) Staphylococcus aureus, (B) Clostridium tetani, (C) E.coli, (D) Yersinia pestis
Answer is C. Coliform organisms: Primary & most reliable bacterial indicator for water quality. E. coli is most impoant coliform indicator. Fecal streptococci: Indicate 'recent contamination of water'. Clostridium perfringens: Indicate 'remote contamination of water'.