Due to the vast number of different species of bacteria which vary in shape, size and growth characteristics, it would be impossible for the ceramic filter to be effective against each type.
However, Doulton® and British Berkefeld® ceramic filters are successful in removing the most prevalent and harmful species, Pathogenic Bacteria.
The pathogenic bacteria that FICL claim to be effective against have been qualified by test data from independent test laboratories or are extrapolated from test data of similar microorganisms (please seek advice from FICL on permitted extrapolated claims).
Although the ceramic will filter all types of heterotrophic bacteria to some extent, it should be noted that any harmless bacteria of this type passing through the ceramic may multiply downstream of the filter.
Since these heterotrophic bacteria are harmless, normally there are no problems and some heterotrophic bacteria are reported to be beneficial to health. However, if normal use of the filter is interrupted by holidays or vacations, growth of these bacteria may result in a ‘flat’ or ‘stale’ taste for a period of time when use of the filter resumes.
This is especially true for the filter elements that contain activated carbon such as the Ultracarb UCC/BTU® (both contain an extruded activated carbon core). Any system containing activated carbon, which will reduce residual levels of free chlorine, will result in an increase in plate counts over a short period of time until a constant state of equilibrium is established.
The UK Drinking Water Inspectorate water regulations call for the water to be regularly monitored for consistency as used, therefore since an equilibrium point is reached in the filtered water, the filters comply with the regulations.
The presence of this type of heterotrophic bacteria does not constitute a health problem since the organisms present will be harmless and a suitable level of consistency would be established. Flushing the filter system for several minutes after any prolonged period of inactivity should eliminate the problem