Coliform bacteria are not pathogenic (disease causing) organisms but are a natural part of the microbiology of the intestinal tract of warm-blooded mammals, including man. Total coliform bacteria are a collection of relatively harmless microorganisms. Coliform bacteria can be found virtually everywhere – in soil, on skin, on animals, insects, in lakes and rivers, etc. Coliform bacteria are indicator organisms, which are used, in water microbiological analysis. When coliforms are present in unfiltered raw water, it is presumed that the larger disease causing organisms (pathogens) accompany them.
A specific subgroup of this collection is the fecal coliform bacteria, the most common member being Escherichia coli. These organisms may be separated from the total coliform and are associated only with the fecal material of warm-blooded animals. Fecal coliforms or E-Coli, is a particular type of coliform bacteria. Their presence in drinking water is more serious than other coliform bacteria because they are disease causing, and also indicate that drinking water has been contaminated by sewage or animal wastes that may contain other disease causing bacteria.
Black Berkey® purification elements have been tested with over one billion E.coli microbes per liter (lawn growth). This contamination level is greater than 10,000 times the colony formation (number of pathogens) typically used when testing a filtration element for its ability to remove E-coli. The results showed no detectable pathogens present within the filtered water (effluent). The water was then incubated. Again, no pathogens propagated and none were detectable when inspected under an electron microscope.
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