Mold/Fungi Investigations

Mold or a mold spore is a microscopic organism that is approximately 2-10 in diameter. To put into perspective the average size of the human hair is 80 – 100 microns in diameter. Mold belongs to the taxonomic kingdom of fungi that contains approximately 1.5 million species. There is a common misconception that mold/fungi are the same thing! Well yes and know. Mold can described as any various form of fungi that can cause a breakdown of any organic matter. Mildew can be described as a superficial fungal growth that is usually white in color and occurs on the surface of plant leaves or other organic material.

Mold is a group of about 200,000 species of fungi. Fungi/Molds occur in both the indoor and outdoor environment. Mold does have a purpose in nature and that is to breakdown or digest dead or decaying organic matter such as dry leaves. Mold/fungi are known and natures recycler. The reason for this is that fungi cannot make it’s own food source thus utilize what is know as extra-cellular digestion to consume organic material.

Mold/Fungi require three elements to grow. An active, moisture source, a food source, and oxygen. A food source can be any organic or cellulose based material from dead leaves to dust or wood and paper drywall backing. Fungi like humans are made up of mostly water so which is why they thrive in moisture rich environments. Mold also prefers areas where there are low levels of ultra-violet (UV) light.

“Fungi can grown on almost any surface provided there is a source of nutrient present.  All fungi require glucose for energy. This simple sugar is usually present in the environment in complex molecules that must be digested before the glucose becomes available for use in producing energy in the fungus. Nutrient sources (food) for some fungi must contain simple sugars or starches that are easily digested. Other fungi produce enzymes that allow the digestion of more complex sugar sources. These complex sugar sources include cellulose, hemicellulose, and lignin. In order to cause wood rot, a fungi must be able to degrade one or more of these compounds.”

Reference: Burge, Harriet The Environmental Reporter, Vol 2, Issue 5


Reproduction of mold occurs with the release of mold spores into the air. When a mold spore lands on a surface or substrate the spore releases enzymes to digest the surface or food source. The mold spore then germinates and produces filaments called hyphae.

The hyphae are the basic cellular unit of the fungi. The hyphae form a protective mat called the myceilium. The myceiliel mat keeps the substrate moist even if the surrounding air is dry. Condia then generate and release mold spores into the air and the process starts over.

The growth cycle of mold can be as little as four (4) to twelve (12) hours. It is left
undisturbed, fungi can spread in 24 to 72 hours. It should be noted that the growth cycle depends on what species of fungi and environmental conditions.


Microbial Volatile Organic Compounds (mVOCs) are the source of “musty” or “moldy” odors that are commonly associated with mold growth. mVOC’s and are the product of metabolism. Exposure to mVOCs from molds have been linked to symptoms such as headaches, nasal irritation, dizziness, fatigue, and nausea.


Mycotoxins are toxins that can be produced by certain species of mold. The mold spore uses mycotoxins (or cytotoxins) to inhibit the growth of other organisms including different species of mold. There are over 300 species of mold that can produce mycotoxins. Exposure to mycotoxins can from come from ingestion, dermal exposure or inhalation.

“Aflatoxin B1 is perhaps the most well known and studied mycotoxin. It can be produced by the molds Aspergillus flavus and Aspergillus parasiticus and is one of the most potent carcinogens known. Ingestion of aflatoxin B1 can cause liver cancer. There is also some evidence that inhalation of aflatoxin B1 can cause lung cancer. Aflatoxin B1 has been found on contaminated grains, peanuts, and other human and animal foodstuffs. However, Aspergillus flavus and Aspergillus parasiticus are not commonly found on building materials or in indoor environments.”


The US Food and Drug Administration has established guidelines for food and feed regarding aflatoxins. Concentrations greater then 20 ppb (parts per billion) is considered a health hazard.

Mold Many Years Ago
Why is mold a problem now and not 50 years ago?  A common material used in building material used in home 50 years ago was plaster or asbestos containing material (ACM). This material is not an adequate food source and is not a suitable substrate for mold to grow on. With the advent of awareness of the health effects related to exposure to asbestos containing material the transition to cellulose based materials occurred and a transition to paper backing gypsum board/drywall was made.

Health Effects of Mold
The approximate size of a mold spore is 2 – 10 microns in diameter. During breathing in humans generally particles greater than 10 microns in diameter will be caught within the nasopharyngeal region (nose). Particles between 2.5 – 10 microns in diameter will typically be caught by cilia lining the bronchial tube walls and will move the particulate out of the lungs. So given the size of the mold spore our nose cannot filter out a mold spore. Only after the spore reaches our bronchial tubes will the mold spore be filtered and pushed out of the lungs by cilia.
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Some people have no adverse health reaction when exposed to mold. Allergic reactions that are similar to animal or pet allergies are the most common. Other health effects such as upper respiratory tract irritation, coughing, asthma etc various from one individual to another. Those individuals who’s immune system is compromised such as cardiac patients, individuals undergoing chemotherapy, elderly, infants etc. are most susceptible to adverse affects from mold exposure.


Fungal Growth Cause and Origin Investigations
Remediation Protocol Development
Microbial Sampling
Clearance Testing
Remediation Project Management
Real Estate Transaction Screening
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