In this exercise,we will focus on bacteriophages of coliform bacteria.Coliform bacteria are relatively harmless microorganisms that live in large numbers in the intestines of mammals,where they aid in the digestion of food. E.coli is a common fecal coliform bactera in water indicates that it has been contaminated with human or other animal feces, and that a potential health risk exists for those who use the water. Raw,untreated sewage comtains large numbers of E.coli.Therefore,we will use raw sewage as a source of bacteriophages that infect E.coli