In practice, two methods are applied:

1. Air germ measurement with a measuring device
   A device (e.g. impaction device) is needed, which draws in a defined air volume, accelerates it and deposits it, for example, on a nutrient strip. The nutrient strip is then incubated and evaluated.
2. Sedimentation method
   Petri dishes are placed open at relevant points in the production process, then incubated and evaluated.