An indoor biological contamination includes molds, mildew, other sources of fungi, bacteria, yeasts, animal dander, insect, bird or rodent scat, and pollen or dust.  The most common form of microbial investigation involves mold or bacteria.  These contaminants originate from water intrusion events.  Typically, these events include roof leaks, sanitary over-flows, pipe breaks, foundation leaks, and catastrophic floods.
Fungi and bacteria are simple, microscopic organisms that are found virtually in every environment. They become a contamination source in elevated colony forming units (CFUs) or organism counts and, dependent upon the Species, can be potentially hazardous to an occupant’s health, especially in immune-compromised individuals.
Fungal (mold) sources of contamination require three basic needs:

1. A food source-generally leaves, wood, paper, dirt, etc.
2. A source of moisture
3. A relatively undisturbed place to grow

Fungal and bacterial investigations often involve sampling. The different forms of sampling used to help with investigations are; air sampling, surface testing and bulk material sampling.

Analytical services should be analyzed by a laboratory, accredited by a nationally recognized, microbiological proficiency program.  Investigative reports depend upon the amount of work done and range from letter of understanding to full reports complete with data, maps, etc.

Many of these investigations are coupled with moisture intrusion surveys which specialize in determining the causes of microbial growth.  Often, the moisture surveys are conducted (with confirmatory sampling) to verify the adequacy of remedial cleanliness following a professional contractor’s remedial work.

Microbial contamination can exacerbate pre-existing problems such as hypersensitivities, asthma and allergies in ways that could be “masked” by the aforementioned conditions.  This makes medical determinations for these organisms as sources difficult and further supports the need for professional expertise.