Occurrence of moulds in drinking water.
OBJECTIVE
In order to determine the occurrence of filamentous fungi in public drinking water systems in Norway, water from 14 water supply networks from all over the country was sampled and analysed. Networks with both ground and surface water sources were included in this study.


RESULTS
During a one-year period, 273 water samples were collected. Frequencies of fungi in samples from raw water, treated water and from home and hospital installations were determined on the basis of incubation of 100 ml membrane-filtered samples on dichloran 18% glycerol agar media. Filamentous fungi were recovered from 62% of all samples. In ground water 42.3% of the samples were positive for mould growth, while surface waters yielded 69.7% positive samples.


CONCLUSIONS
The risk to recover moulds from surface water is three times higher compared with ground water. It is more likely to detect moulds in cold waters and showers than in hot waters.


CONCLUSIONS
By analysing the water reaching the consumers, the results reported in present study indicate that filamentous fungi in drinking water is not negligible, and that moulds should be considered as part of the microbiological analysis parameters in drinking water.
Hageskal
G
G
National Veterinary Institute, Section for Food and Feed Microbiology, Oslo, Norway.
Gaustad
P
P
Heier
B T
BT
Skaar
I
I
D003470:Culture Media; D004326:Drinking; D004784:Environmental Monitoring / Q000379:methods; D005618:Fresh Water / Q000382:microbiology; D005658:Fungi / Q000302:isolation & purification*; D006358:Hot Temperature; D009664:Norway; D018570:Risk Assessment / Q000379:methods; D012621:Seasons; D014871:Water Microbiology; D014881:Water Supply
D003470:Culture Media