26 August, 2020. Apollo Bay. Detection of Escherichia coli in drinking  water (1 MPN/100ml).

On 26 August, Barwon Water was notified of a detection of E. coli and notified DH under
section 22 of the Act. The E. coli was detected in a water quality sample taken the previous
morning from a distribution tank in the Skenes Creek High Level system in the Apollo Bay
locality. The tank supply 5 supply-by-agreement customers.

An investigation was carried out in accordance with Department of Health (DH) guidelines,along with corrective actions which included system review, retesting of the original sample and chlorine dosing followed by sampling.The follow-up samples were free of E. coli and total coliforms. The Department of Health made an assessment requiring Barwon Water to submit a section 18 for noncompliance with the E. coli water quality standard. This was based on not meeting all of the criteria required to claim a false positive outcome. All contributing factors
have been addressed in order to prevent future reoccurrence.

“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