"E. coli" normally grow in soil and in the large intestines of many mammals, including humans. Most strains of "E. coli" do not cause disease, but instead help animals get vitamins and digest food. Some strains of "E. coli" cause sickness in people. "E. coli" are not usually in food or water. When food has not been prepared with clean equipment, "E. coli" can grow in the food. When "E. coli" are found in water, this may mean that the water has touched sewage. 