The two strains exist in different environments

The two strains exist in different environments thus have different growing conditions. For instance, E. coli is found in the human bodies that has an optimum of about 37degrees centigrade. While Bacillus stearothermophilus was removed from a pool with temperature was approximately 45 degrees. According to this we can see that generally Bacillus stearothermophilus grow in a slightly temperature as compared to E. coli. The increase or decrease in temperature would definitely alter the growth mechanisms thus affecting bacteria growth and eventually affecting their abundance in an environment. In regard to the temperature microorganisms can be classified into three psychrophilic, thermophiles and mesophilies.