Efficiency of medium containing a low concentration of organic nutrients in the enumeration of thermophilic bacteria from hot water.
Thermophilic bacteria from drinking and hot water samples in Finnish buildings were enumerated at 50 degrees C on media with low (R2A) and high (tryptone yeast; TY) concentrations of organic nutrients. In both types of water, the maximum viable counts were obtained on R2A medium. In hot water samples, the plate counts at 50 degrees C were 86 times higher on R2A than on TY medium. In hot water distribution systems, the difference between these media was highest in taps and showers where R2A medium produced 130 times higher plate counts than TY medium. The difference between the plate counts with these media was higher in hot water in the buildings supplied with processed groundwater than those supplied with processed surface water. In hot water samples originating from groundwater and surface water, the plate counts with R2A medium were 280 and 25 times the counts with TY medium, respectively.
Laboratory of Environmental Microbiology, National Public Health Institute, Kuopio, Finland.
O M
OM
Zacheus
P J
PJ
Martikainen
D001419:Bacteria / Q000254:growth & development*; D015169:Colony Count, Microbial; D003470:Culture Media; D005387:Finland; D006358:Hot Temperature; D014871:Water Microbiology; D014881:Water Supply
D003470:Culture Media