Which of the following is considered as an ideal bacteriological indicator as acceptability aspect of water: March 2013 (d)

Ans. C i.e. Clostridium perfringenes Clostridium perfringens Gram-positive, spore-forming, non-motile, strictly anaerobic rods that reduce sulphite to H2S, but also ferment lactose, sucrose and inositol with the production of gas, produce a stormy clot fermentation with milk, reduce nitrate, hydrolyse gelatin and produce lecithinase and acid phosphatase. Bonde (1963) suggested that not all SRC (sulphite reducing clostridia) in receiving waters are indicators of faecal pollution, hence C. perfringens is the appropriate indicator.