Mold Test Kit Review
Air vs.
Surface Sampling Techniques
Reviews of
Various Mold Tests
Note on Mold Testing:
Mold tests by themselves cannot give you
the full picture of the mold problem in your house or
building. When combined with other evaluation
methods (such as those listed at: "Signs
of a Mold Problem") you can better
determine the extent of the problem.
Since they can be expensive, and usually
tell you only what you already know, it is usually best to
find the source of excessive moisture and to try fixing it
before resorting to a mold test (Finding
Mold, Preventing Mold, Cleaning
Up Mold).
Some techniques identify what species of
molds are present. This can be helpful since some mold species
pose a greater health risk than others.
Air
vs. Surface Sampling Techniques
Mold tests can be divided into two
categories: air and surface. If you find it necessary to
perform a mold test (e.g. for legal purposes), then it would
be advisable to take at least one surface sample and one air
sample.
The reason is, in some situations, you may
have mold growing on surface, yet it has not reached a point
where it is releasing very many mold spores into the air. In
which case, air sampling alone would provide results that did
not accurately portray the extent of mold growth.
Or, you may have a situation where, in your
random surface sampling, you did not sample a surface where
mold was growing (or at least not at a significant level), but
mold colonies throughout other parts of the home had reached a
point where they were releasing substantial amounts of mold
spores into the air. In this case, your surface sampling would
not give you and accurate picture of the problem.
Reviews
of Various Mold Tests
Anderson N-6 Bioaerosol Sampler:
This is a single stage petri plate impacter
that consists of an aluminum device held together by 3 spring
clamps and is sealed with O-ring gaskets.
A high volume of air is drawn through the sampler
causing multiple jets of air to direct airborne particles
toward the surface of the agar collection plate.
This will lead to biological growth if any
microorganisms are present in the air that is sampled.
A short collection period (3-5 minutes @ 28.3 lpm)
should be used to prevent the plates from being overgrown by
microorganisms. The
sampler should be disinfected with isopropyl alcohol between
each use and you don not want to use media that’s expired,
has visible cracks, or possible contamination.
Pros:
Results relate directly to airborne exposures;
qualitative and quantitative results; it is possible to
speciate; specific organisms can be targeted since various
types of media are available; results can be compared to bulk,
tape, or swab results in order to find amplification sites.
Cons: Expensive;
time consuming for sampling and analysis; only isolates viable
(living) organisms; some fungi may overgrow others leading to
an unclear picture about what is present; media has a short
shelf-life; and the samples are perishable if not handled
properly and carefully.
Spore
Trap:
This
indoor air quality sampler is a particulate sampling cassette,
Zefon Air-O-Cell Cassette, designed for rapid collection and
analysis of a wide range of airborne aerosols including mold
spores, pollen, insect parts and skin fragments.
These types of samples are used to detect for total
spore counts. It is
useful for rapid analysis of airborne contaminants in IAQ
testing, allergy testing and flood restoration monitoring.
Pros:
Media is easy to store and has a long-shelf life;
results are semi-quantitative and relates directly to airborne
exposure; rapid analysis of results.
Cons:
Differentiation between viable and non-viable organisms
is difficult; can’t sample for bacteria; there is large lab
to lab variation in analysis of results; and cannot speciate.
Bulk/Surface
Samples:
These
types of sample are applicable when there is visible
contamination of building materials such as drywall, flooring,
insulation, wood, etc. Materials
are collected then sent directly to a lab for microbial
identification. Bulk/ surface sampling is useful in
verification of remediation.
Pros:
Inexpensive; rapid spore count identification; can be
quantitative; able to differentiate between viable and
non-viable microorganisms; possible to culture and then
speciate.
Cons:
Destructive of building materials; may expose occupants
during collection; results do not relate directly to airborne
exposures; may not be the source of contamination.
Wallchecks:
Wallchecks
evaluate concealed spaces without being destructive.
Pros: Results
are qualitative and quantitative; media is easy to store and
has a long shelf-life, results
relate directly to spacial contamination and to the
contamination of the air behind the wall, cabinet space, etc;
rapid analysis of results.
Cons:
Differentiation between viable and non-viable is
difficult; cannot collect samples for bacteria; lab to lab
variation in results is great; cannot speciate; the lack of
dilution ventilation may cause high levels for results that
are not representative of the problem.
Swab/Tape
Sampling for Building Surfaces:
A
swab sample is collected with a sterile cotton “Q-tip”
applicator that has been moistened with sterile growth media.
The area to be swabbed should be performed by a person
wearing sterile latex, surgical gloves and the cotton head of
the applicator is broken off into the growth solution vial.
The vial and swabbed applicator sent to a lab for plate
culturing and counting.
Pros: Inexpensive;
non-destructive; rapid analysis for spore counts; results can
be quantitative and cultured for speciation; sampling can be
performed on irregular surfaces.
Cons:
Results do not relate directly to airborne exposures;
fungal structures may be damaged during collection causing
identification of the mold to be less accurate; spores may
germinate before lab analysis; may miss presence of organisms
in porous materials; and sample collection does not work well
on dry surfaces.
The ProLab Mold Test Kit:
Offers three (3) different types of sampling methods,
depending on your application needs:
Method 1: taking a sample from a visual growth area.
The same as bulk/surface sampling (covered above).
Method 2: taking a 10 minute grab air sample of the
HVAC system. This is done by placing a petri dish over a
register, closing all other registers, and turning the HVAC
system fan on and sampling for 10 minutes. Close the plate up
and allow it to incubate for a couple of days.
Method 3: taking an air sample using a settling
plate technique. This is simply done by placing an open petri
dish somewhere in a room for like an hour, closing it up, and
allowing the plate to incubate for a couple of days.
Pros: Results may relate to airborne
exposures; qualitative results; it is possible to speciate;
results can be compared to bulk, tape, or swab results in
order to find amplification sites: Methods 2 & 3 are
beneficial for finding mold in the HVAC system.
Cons: Time consuming for analysis; only
isolates viable (living) organisms; some fungi may overgrow
others leading to an unclear picture about what is present;
and the samples are perishable if not handled properly and
carefully; would not be quantitative since it does not employ
using a specified flow rate, therefore you cannot calculate a
quantity in a sample of air.
Signs of Mold -
22 signs that you may have a potential mold problem in your
home or building.
How to Find Mold
- Where to look and ways to uncover mold growth in your
home or building. |
