Coliphages

Coliphages are a group of bacteriophages that infect and replicate within coliform bacteria. Male-specific coliphages infect only the E. coli bacteria that express certain physical appendages used during sexual conjugation (pili). Somatic coliphages adsorb directly into the E. coli cell wall. Both male-specific and somatic coliphages are used as surrogates to indicate the presence of fecal material and viral pathogens in water.

They are excellent candidates to determine log removal by treatment process, such as wastewater treated by UV, ozone, chlorine, and filtration. They have been suggested to be an alternative to human enteric virus testing for biosolids since they provide more useful outcomes with quicker results and are inexpensive to test for in relation to enteric viruses. Coliphages are detected using either a presence-absence assay (EPA method 1601) or an enumerative assay (EPA method 1602).