Why Sample for Biological Materials?
The goal of biological sampling is to help determine whether the biological particles present in a particular environment are affecting or causing irritation in certain individuals. Sampling is also used to locate the sources of indoor microorganisms and facilitate an effective remediation. While we are typically surrounded by a wide variety of different microorganisms every day, sampling provides us with a method to establish in a scientific way whether the environment in question contains more organisms than would normally be present. There are numerous techniques that may be used to evaluate the level of indoor microorganisms. We believe, however, that scientific comparisons are only possible when measured volumes of air are sampled and when results of surveys are expressed in terms of volumetric measurements.
Culturable vs. Non-culturable Methods
Currently, there are no widely accepted protocols or regulations regarding biological air sampling. In the absence of standards, we believe that common sense should prevail. We know that some bacteria and fungal spores can cause disease only when they are alive (viable), while others are capable of producing allergies or irritation even when no longer living. Also, while cultures may permit greater accuracy in speciating some fungal organisms present, spores vary widely in their ability to grow and compete on laboratory media. This may result in an inaccurate characterization of the area sampled. Therefore, a complete sampling protocol for the biological flora in any environment uses both a culturable and non-culturable sampling method. There are times when this is not possible due to time and budget constraints. In these cases, we currently believe that a non-culturable spore trap sample provides a more accurate "snapshot" of the air and is usually the best choice when only one sampling method can be used.