2.3.5. Biological indicators
A portable air sampler (SAS Super IAQ, pb international CO.) for semi-solid medium (Agar plates) with a constant air flow rate of 100 L/min was used to carry out the biological sampling for determining the concentration of bacteria and fungi in the air. The medium used for the collection and further laboratorial culture of bacteria was tryptic soy agar (TSA), while the collection of fungi was made on malt extract agar (MEA). Each of these measurements was taken over a period of 2.5 min to get an air sample of 250 L. After incubation in laboratory under specific temperature conditions, each plate is analyzed and the results of counting are expressed in colony-forming units per cubic meter of air (CFU/m3).