Microbiological air testing is an important part of cleanroom qualification as it helps to monitor and ensure the quality and cleanliness of a cleanroom and the maintenance of hygiene standards.

Microbiological air analysis

Sensitive products, such as pharmaceutical products and medical devices, are manufactured in cleanrooms. Contamination of these products with microorganisms can lead to serious health risks or quality problems. It is therefore crucial to continuously monitor the microbiological quality of a cleanroom.

In microbiological air testing, samples are taken using sedimentation plates (passive sampling) or an air sampler (active sampling). In passive sampling, the microorganisms in the air passively sediment on the culture medium and can grow into visible colonies. In active sampling using an air sampler, the air and the microorganisms it contains are actively sucked in and directed onto the culture medium, where the microorganisms can then grow into visible colonies.

The culture media from the passive and/or active sampling are then incubated in the laboratory and examined for colony growth.
The colony-forming units (CFU) are determined on the culture media plates.

The results of the microbiological air tests are documented in the form of reports and these can be used to document the cleanroom status as well as for statistical checks (e.g. trends, outliers) and to derive measures.


  • DIN EN 17241
  • GMP Annex 1

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