Enumeration of salmonellas by most probable number method from sewage and sewage-polluted natural waters, comparing the use of preenrichment versus direct enrichment in NR10 at different temperatures.
Crude sewage and sewage-contaminated natural waters were analysed for the presence of Salmonella by Most Probable Number Procedures, Direct enrichment in NR10 at 37 degrees C and 43 degrees C was compared with preenrichment in buffered peptone water at these two temperatures, followed by selective enrichment in NR10 at 37 degrees C and 43 degrees C. The growth of competing bacteria on Hektoen agar plates was also recorded and quantified. Direct enrichment in NR10 gave higher numbers in both types of waters. The temperature of 37 degrees C was more favourable for the less heavily contaminated waters, whereas 43 degrees C was more efficient for crude sewage. The growth of competing bacteria was restricted at 43 degrees C and enhanced at 37 degrees C. With direct enrichment in NR10/43 degrees C, pure Salmonella cultures can be obtained after 48 h incubation.
D003470:Culture Media; D012475:Salmonella / Q000254:growth & development*; D012722:Sewage; D013696:Temperature; D014871:Water Microbiology
D003470:Culture Media; D012722:Sewage