Recovery Comparison Study
Aerosols of three different bacteria suspensions are released into a sampling channel under defined conditions. At the end of the channel the aerosols are sampled using four different air monitoring methods. As a reference method two parallel impinger systems were used (100 % recovery).

BACTair™ shows the highest recovery of bacteria due to optimized geometry and complete disposable design.

Correction Factors
The recovery of colony-forming units depends on the number of holes in the sieve plate onto which the air is impacted. The lower the number of holes, the higher is the risk that more than one microorganism will pass into one single hole (colony overlapping).

A correction factor (K) can be calculated mathematically:
K = x · (ln(x)-ln(x-n)) x = number of holes in the sieve plate n = colony count.
BACTair™ provides 400 air impaction holes. A correction factor is only relevant with very high CFU counts.

Evaporation Effects
During the sampling period, agar media may dry out, thus inhibiting the growth of the collected microorganisms. The weight of several BACTair™ was measured prior to and after sampling and compared to other impaction agar plates or strips.

Because of its optimal design BACTair™ shows the lowest desiccation effects and enables viable microorganisms to grow under optimal conditions.

The number of impaction-holes and their optimal position in relation to the sampling area are the key to reliable results.