2012 May – East Frankston – Willow Road (Victoria) – E.coli

East Frankston – Willow Road – Victoria – E.coli
The fifth event was a detection of E. coli from a routine sample taken in Willow Road, East Frankston on 3 May 2012. 5 organisms per 100mL were detected, and the free chlorine residual at the site of the detection was 0.47 mg/L. This sample tap falls in the Karingal locality. The sample tap is the detention point from the East Frankston secondary chlorinator on the outlet of the East Frankston tank. The area was flushed and all system checks were clear, including the chlorinator operation. Resamples were taken the following day from the sample tap in question, two nearby sample taps and the East Frankston tank, and all were free from E. coli.

Escherichia coli should not be detected in any 100 mL sample of drinking water. If detected
in drinking water, immediate action should be taken including investigation of potential
sources of faecal contamination.

“Coliforms are Gram-negative, non-spore-forming, rod-shaped bacteria that are capable of aerobic and facultative anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are found in large numbers in the faeces of humans and other warm-blooded animals, but many species also occur in the environment.

Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG 2011