Why are Total Coliform bacteria used as an "indicator organism" for drinking water safety rather than testing directly for specific pathogens?

• Testing for them takes only a few minutes compared to other bacteria.
• Coliforms are the most lethal type of pathogen found in water.
• They are easy to detect, abundant in feces, and their absence generally indicates the absence of harder-to-detect pathogens.
• They are the only type of bacteria that can survive the chlorination process.