Coliform Bacteria
Introduction to Coliform Bacteria
Coliforms are several types of bacteria that can be found in the soil, on vegetation or on surface water. Some of the Coliforms live in the intestines of people and warm-blooded animals. However a great number of the Coliforms are neutral to people, they indicate that harmful to human microorganisms are present.
Coliforms are used to indicate the quality of drinking water. A large number of different bacteria, including: Escherichia, Enterobacter, Klebsiella, Serratia, Citrobacter and Proteus belong to the total Coliform group. The fecal Coliform group is an under-group of the total Coliforms and has fewer bacteria.
Total Coliform bacteria live in soil, in water or on vegetation and are usually innocuous. If total Coliform bacteria are found in the drinking water that means the source of contamination is environmental. Feces contamination is not likely, however if these bacteria managed to enter the water system, other pathogens may also do, so it is crucial to determine the source of contamination.
Fecal
Coliform bacteria are a sub-group of the total Coliform group. They can
be found in the intestines and feaces of people and animals. The
presence of fecal Coliforms in the drinking water often indicates recent
fecal contamination. That means higher risk of pathogens presence. E.coli is a genus and species of the fecal Coliform group. E.coli is present in the intestines of warm-blooded animals and humans. The presence of E.coli in drinking water in almost all cases signify fresh fecal pollution. Most E.coli strains are harmless, (except the strain E.coli 0157:H7) but the presence of E.coli in the water indicates high probability of disease-causing microorganisms.
The Coliform microorganisms do not change the color or taste of the water. The only way to find out if they are present in the water is a laboratory test. They can all be destroyed by boiling water.
