Settle plates (also known as sedimentation plates or settling plates) are used in the pharmaceutical industry for semi-quantitative determination of microbial contaminations in the air. The plates Merck provides are also suitable for personnel monitoring, e.g. gloves.

Passive monitoring uses “settle plates”, which are standard Petri dishes containing culture media, which are exposed to the air for a given time in order to collect biological particles which “sediment” out and are then incubated. Results are expressed in CFU/plate/time or in CFU/m 2 /hour [ 22 ].

Active air monitoring with settle plates or contact plates requires the use of a microbiological air sampler to physically draw a certain, pre-determined volume of air and pass it over the agar. The plate is then removed from the air sampler and directly incubated, allowing visible colonies to develop and subsequently be counted.