How do I dispose of Easicult?
Any growth on dipslides may be pathogenic. Therefore, used slides should be disposed of by burning, autoclaving or by immersion in a disinfectant overnight, always following local laws and regulations.
Are all colonies on the ‘pink side’ of the Easicult Combi dipslide considered to be yeast or mould? Are all colonies on the ‘pale side’ considered to be bacteria?
The ‘pink side’ is Rose-Bengal agar for the detection of yeasts and moulds. It contains antibiotics in order to inhibit the growth of bacteria. However, it is possible but rare for some bacteria to be resistant to these antibiotics.
The ‘pale side’ is TTC agar, which promotes the growth of most bacteria. The same is true for the bacterial agar. In addition, many yeasts and moulds may still appear on TTC agar which does not contain inhibitory substances. Usually, yeasts and moulds need a longer time for growing, whereas bacterial colonies appear earlier.
My test surface turned red or pink almost immediately. Do I have lots of bacteria?
No, this is most likely a chemical reaction. The TTC dye on Easicult TTC and Easicult Combi (TTC is added to the media in order to colour the colonies red) reacts when the nutrients in the media are broken down. This reaction may be caused by bacteria or even by certain chemicals. If the colour change is due to a chemical reaction, it should happen within the first 15 - 30 minutes. Also, no colonies would be visible on the test surface within that time period.
What does 103, 104, 105, etc. mean?
The superscript number specifies the power of 10. If a sample is interpreted to contain 103 micro-organisms/ml, this means that there are 10 × 10 × 10 or 1000 micro-organisms present. If 104 micro-organisms are present, this equals 10,000 micro-organisms, and so on.
I have had results back from a laboratory but I am not sure what they mean.
Total Plate Counts, Total Viable Counts (TVCs) and Plate Counts are different terms applied to carrying out ‘Total Bacterial Counts’. A laboratory will normally report the results by colony forming units (CFUs). For example: 2.4 × 103 indicates that 2400 CFUs were identified per millilitre. The result from Easicult carried out on the same sample would have been interpreted as 103 CFU/ml.
I incubated my tests for longer than 48 hours. Is this a problem?
It is acceptable to incubate the tests for 48 hours or more. In many cases this is recommended in order to allow slowly growing organisms to appear.
The kit instructions specify an incubation period of 24 - 36 hours. How long should I incubate the tests?
If you are incubating the tests at room temperature, we recommend an incubation period of 2 - 4 days. If you are incubating the tests at 30 ºC, the tests can be read after 24 hours and then returned to the incubator and checked again after 48 and 96 hours.
Some grown colonies are very large. Does this mean I have more micro-organisms?
No, the ‘dot’ or colony size is independent of the number of micro-organisms. In principle, the fewer microbes there are, the more space and nutrients are available for them which may lead to bigger colonies. However, this is not always the case.
Does any Easicult product identify specific micro-organisms such as Legionella or other pathogens?
The identification of specific micro-organisms is more complex and usually performed only in a microbiology laboratory. Easicult dipslides are not intended for detecting specific pathogens.
Do the tests need to be incubated in the light or in the dark?
Either is acceptable because the presence of light has no impact on the test itself. However, exposure to direct sunlight should be avoided during the storage and incubation.
Some of colonies that have developed are not red on Easicult TTC agar. What does this mean?
The colonies turn red because of the indicator dye. This dye is added to make the results interpretation easier with more visible colonies. Certain bacteria may occasionally form colourless colonies on this medium.
How should I store Easicult?
Easicult should be stored in the kit box at room temperature, protected from draughts and temperature fluctuations in order to preserve the moisture content and the balance of nutrients in the medium. Avoid freezing and direct sunlight.
The test kit instructions specify the incubation temperature range. What is the actual required temperature for incubation?
If you have an incubator, incubate the tests at 27 - 30 ºC. If you do not have an incubator, incubate the tests at ambient temperature or at room temperature (18 - 25 ºC). Extended incubation time may be recommended in lower temperatures. The most accurate results can be obtained when the slides are incubated at the temperature where the samples have been collected.
What is an acceptable number of bacteria for cooling water to contain?
A general guide would be 103 - 104 CFU/ml for cooling water. However, you should determine the acceptable level of bacteria for your specific system.
I have a box of Easicult which is past its expiry date. Can the tests still be used?
The Easicult tests have an expiry date printed on the side of each box. The expiry date has been determined based on real-time stability data and the product should not be used after its expiration date.