Background
AMS Laboratories has now been accredited by NATA for the testing of environmental water for a range of microbiological tests. Waters that can be tested include; drinking water, recreational water, swimming pools and spas and wastewater.
The tests include indicators of both the overall water quality and of possible sources of contamination. All tests are performed by membrane filtration to meet the requirements of the current Australian Standards.
For further information on NSW regulations, please visit
http://www.health.nsw.gov.au/PublicHealth/environment/water/index.asp
Accredited tests include:
TMW 140 Heterotrophic Plate Count
Principle of the Test
Pour plates are performed on the sample at a suitable dilution range. 2 temperatures are employed since many waterborne micro organisms will not grow at elevated temperatures. Conversely micro organisms indicating poor hygiene will generally grow well at higher temperatures. Incubating plates at both temperatures gives a better overall picture of the water quality.
TMW141 E. coli and Thermotolerant Coliforms
Principle of the Test
These micro organisms are useful indicators of possible faecal contamination of water and also suggest that there may be other pathogenic bacteria, parasites or viruses present. A suitable dilution, or range, is filtered and the membrane transferred to a selective agar plate and incubated at an elevated temperature (44°C). Following incubation suspect colonies are counted and confirmed.
The thermotolerant coliforms group includes E. coli and number of other similar bacteria.
TMW 142 Coliforms
Principle of the Test
The test for the presence of coliforms is a more general test than that for E. coli and Thermotolerant Coliforms and includes many non-pathogenic species. However, being
a broader test it has the potential to detect contamination in water where pathogenic species are present in only very small numbers.
A suitable dilution, or range, is filtered and the membrane transferred to a selective agar plate and incubated at 37°C. Following incubation suspect colonies are counted and confirmed.
TMW 219 Enterococci
Principle of the Test
These micro organisms are useful indicators of possible faecal contamination of water and also suggest that there may be other pathogenic bacteria, parasites or viruses present.
A suitable dilution, or range, is filtered and the membrane transferred to a selective agar plate and incubated at 44°C. Following incubation suspect colonies are counted and confirmed.
TMW 220 Pseudomonas aeruginosa
Principle of the Test
P. aeruginosa is an opportunistic pathogen commonly found in soil and water. It is able to tolerate and grow in a very wide variety of conditions. In poorly or untreated water it has the potential to cause skin and ear infections and is of particular concern in spa water where the elevated temperature serves to reduce competition.
A suitable dilution, or range, is filtered and the membrane transferred to a selective agar plate and incubated at 42°C. Following incubation suspect colonies are counted and confirmed.
TMW 221 Pseudomonads
Principle of the Test
This test includes members of the Pseudomonas genus, as well as several other genera which have similar growth characteristics. Some of these were previously classified in the genus Pseudomonas, but have since been removed.
Pseudomonads are commonly found in soil and water. The group includes opportunistic animal and plant pathogens such as P. aeruginosa and Burkholderia cepacia, a number of causative agents of spoilage and some species have uses as biocontrol and bioremediation agents.
A suitable dilution, or range, is filtered and the membrane transferred to a selective agar plate and incubated at 21°C. Following incubation suspect colonies are counted and confirmed by a number of steps.
Sampling
Sample size is dependent on the quality of the water to be tested. As a general guide, at least 100mL per test should be submitted.
Turn Around Times
Again this is subject to the quality of the water being tested and the confirmation testing required for each of the tests. The duration is summarised in the table below
|
Test
|
Minimum duration
|
Confirmation testing
|
|
HPC 21°C
|
3 days
|
N/A
|
|
HPC 37°C
|
2 days
|
N/A
|
|
E. coli
|
1 day
|
1 day
|
|
Coliforms
|
1 day
|
1 day
|
|
Enterococci
|
2 days
|
1 day
|
|
P. aeruginosa
|
2 days
|
1 day
|
|
Pseudomonads
|
2 days
|
8 days
|
|
