E. coli was grown on MacConkey Agar (MAC) at 37 degrees for 24 hour. MAC is a Selective and Differential media used to inhibit G+ growth and some G- bacteria as well as identify and isolate lactose fermenting G- enteric bacteria mainly Enterobacteriaceae. Strong lactose fermentation produces pink colonies with bile salt precipitation (hot pink) as seen around the growth on the plate. Weak fermentation produces pink colonies. MAC can be used to screen for Enterobacteriaceae or Fecal Coliforms in environmental sample such as water. E. coli is used as an indicator organism for fecal contamination in a sample.