Drinking water scheme
| No. of registered laboratories: | around 150 |
| No. of laboratories per round: | 100-125 from 10 countries |
| No. of rounds per year: | 2 |
| No. of samples per round: | 2-4 |
| No. of analyses per round: | 9-12 |
| No. of organisms per sample: | 2-6 (bacteria and/or micro fungi) |
| Analyses | Method principle |
|---|---|
| At every round | |
| Coliform bacteria (membrane filtration method = MF) | Membrane filtration method |
| Escherichia coli | Membrane filtration method |
| Culturable microorganisms (”total count”), (22 ± 2) °C after 3 days | Pour plate technique |
| Coliform bacteria & E. coli (alternative methods) | Rapid method with quantification by MPN |
| At least once a year | |
| Culturable microorganisms (”total count”) at (36 ± 2) °C after 2 days | Pour plate technique |
| Intestinal enterococci (MF) | Membrane filtration method |
| Pseudomonas aeruginosa (MF) | Membrane filtration method |
| Clostridium perfringens (vegetative cells + spores) | Membrane filtration method |
| Micro fungi (mould and yeast) | Membrane filtration method |
Only those analyses that are of interest have to be performed.
In addition to the analytical parameters above, results of so-called suspected organisms can be reported for the MF-methods (except micro fungi). That means all typical colonies appearing on the primary MF media – i.e. before any confirmations. The analysis of suspected thermotolerant coliform bacteria may also be reported, which is, sometimes, the first step for the analysis of E. coli. The reported results of suspected organisms are not evaluated and have to be checked by the participating laboratory itself in the final report. These results are used as informative data for discussions of the overall analyses outcome.
Both simple sample mixtures covering all the analyses in a round (vials with white labels) and challenging sample mixtures (vials with blue labels) can sometimes be included in a testing round.
Testing rounds to come
The analyses in the testing rounds of the current and next year can be studied on: