Mold Testing

Mold Testing is the third step of a mold assessment. This step is optional and only necessary if results obtained during the mold inspection and moisture testing require clarification. For example, if suspicious spots are indeed mold or something else, and if it is a contamination or a real mold infestation.

I can offer three different methods of mold testing (sampling):

  • tape-lift samples from surfaces
  • material samples (bulk samples)
  • air samples

Tape-lift samples:

Tape-lift samples are an easy-to-use, inexpensive and fast method for the detection of living as well as dead fungal components on surfaces.

The samples are then examined microscopically in a laboratory. Most molds can be identified at genus level and a few at species level.

The method detects fungal structures such as spores, mycelium, sporangia and spore carriers and can provide a lot of additional information.
Adhesive film samples are well suited for the detection of Stachybotrys chartarum.

Advantages:
▪ Simple sampling
▪ Detection of the mold structure
▪ Differentiation: active damage, old damage
▪ Detection of non-cultivable fungi
Disadvantages:
▪ Differentiation only possible to a limited extent
▪ Only local assessment possible

Material samples:

A piece of the possibly infested material should be removed, wrapped in aluminum foil and sent to a laboratory. The information on the contamination is given in CFU/g, the molds are determined at genus or species level.
Suitable samples are, for example Screed samples, pieces of wallpaper, plaster, insulating wool, wood samples, silicone joints, paper, fabrics, shoes, etc.
Material samples can be used to make statements about the penetration depth of fungi into the material.
Depending on the test method, only living, viable fungi or living and dead components can be detected in material samples.
A mold test is only necessary if results obtained during the inspection and moisture measurement require clarification.

Advantages:
▪ Indication of the source (plaster / wallpaper / screed / wooden parts / potting soil/etc.)
▪ Determination of the infestation level of the material, also microscopically
▪ Cultivation and differentiation of mold fungi (total CFU/g or CFU/cm2)
▪ Detection of molds with particular health significance
Disadvantages:
▪ Contamination possible
▪ Only local evaluation possible
▪ Sample the front and back of infested wallpaper.

Air samples:

Air sampling may be necessary if an individual(s) has been diagnosed with a disease that is or may be associated with mold exposure (e.g., aspergillosis) and the physician/medical practitioner desires to confirm the causative agent.

Air sampling may be considered if the presence of mold is suspected (e.g., musty odors) but cannot be identified by a visual inspection or bulk sampling (e.g., mold growth behind walls). The purpose of this sampling is to determine the location and degree of contamination.

Air sampling should not be used, if mold is already visible. For more information on the pros and cons of air sampling, take a look at this blog post.

In airborne mold testing, airborne spores are collected and cultivated according to a standardized procedure. The air spores are applied directly to culture media.

The results of the room air measurement are given as “colony-forming units” (CFU) per cubic meter of air (cfu/m³).

With the help of the measurement of cultivatable molds in the room air, the types of molds contained in the room air can be determined. These can also provide indications of moisture damage as well as the causes of damage. Furthermore, the room air can also be checked for indications of molds that are relevant to health.

The measurement of the concentration of cultivable molds in the indoor air is a snapshot, which is also influenced by the outdoor air concentration.

In order to determine the indoor contamination, samples of the outdoor air are also taken, because there are always mold spores in the air and only the comparison of the two samples can indicate a hidden mold infestation.

Advantages:
▪ Can be used for health-related questions
▪ Precise determination of the mold species
▪ Provides information on the total number of viable mold spores in the room air
Disadvantages:
▪ Laboratory results only after > 14 days
▪ Dead spores and species that do not grow on the usual culture media are not recorded
▪ Some species, such as Stachybotrys chartarum, have “sticky” spores that are generally not detectable in indoor air (unless the material / surfaces have been improperly dried). Adhesive film samples are better suited for the detection of Stachybotrys chartarum.

No Conflict-Of-Interest. Ever!

J.M.W. Geo-Consulting is an independent, certified testing company that never conducts remediation.
I also use independent, accredited testing labs.
Therefore, J.M.W. Geo-Consulting’s results are always unbiased and accurate.

 
 

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    J.M.W. Geo-Consulting
    Bouwerij 4 B
    1185 XX Amstelveen
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