N. 109 - Agar moisture loss in Petri dish using an impact air sampler system

The optimal growing of colonies on a culture plate is obtained with an agar medium that has the correct volume, the correct level of moisture and is freshly prepared. The agar plates can lose moisture for high temperature during the storage and during the air sampling due to the impact of air on the agar surface. According to the literature the loss should be lower than 10%. It is here reported an example of SOP (Standard Operative procedure) to evaluate the loss of humidity on Petri dish during the air sampling by an active air sampler.