Compact Dry AQ

Art. No.: HS9541 / HS9542

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Product info

Intended use

Usage of Compact Dry AQ is a simple and safe test procedure for determination and quantification of heterotrophic water bacteria from water samples (drinking and ultrapure water). The ready-to-use plates consist of a special 50 mm diameter petri dish containing a detection specific nutrient pad.

General Information

Standard methods for determining the total viable bacterial count of heterotrophic bacteria in water usually recommend nutrient-rich media and incubation at 36 ± 1 °C. In some cases, only part of the actual microorganisms in the sample can be detected under these conditions. Therefore, a longer incubation period and a lower temperature are specified for the nutrient reduced Compact Dry AQ. This ensures that stressed or chlorine tolerant bacteria can also be revitalized and cultivated. Microorganisms, such as bacteria, yeasts and molds, can be cultivated using Compact Dry AQ.

The ready-to-use plate is also particularly suitable for the membrane filter method. A 47 mm mixed cellulose ester (MCE) filter with 0.45 μm pore size should be used for this task. After water filtration, the filter should be placed in the middle of the previously moisturized Compact Dry plate completely free from bubbles and with the trap side facing upwards. After applying the water sample (1 ml) or preparing saline solution (1 ml prior to filter application), the dehydrated Compact Dry AQ plate becomes gel-like. The liquid self diffuses evenly. Further steps, for example manual spreading, are not required.


  • Compact Dry AQ is therefore an extremely easy-to-use method that produces the same results as the standard ISO method for detecting heterotrophic bacteria in water.
  • Compact Dry AQ is also convincing due to the high time saving; a confirmation test is also not necessary.



Art. NoHS9541 / HS9542
Test formatHS9541: 100 nutrient plates,
HS9542: 40 nutrient plates,
four plates are packed in one aluminum bag.
Sample preparationViable count in water samples or using filter technology
Incubation time44 ± 4 hours at 36 ± 2 °C,
68 ± 4 hours at 22 ± 2 °C (ISO 6222:1999)
Validated matrices

Drinking and ultrapure water

Detected analyte

Heterotrophic water bacteria = red colonies;

yeasts = white-pink colonies;

molds = 3-dimensional cottony form.

EvaluationVisual counting