Freaquently Asked Questions

Interview with Dave Gallup
EMLAB—San Bruno, CA

1. What is your position at EMLAB?
Chief Executive Officer.

2. What are your responsibilities?
In short, it is to make sure that we achieve our mission statement stated below. When IAQ professionals ask, "Who is the best environmental microbiology lab in the nation?" the answer should be "EMLab." In pursuit of this goal, we strive to be an effective, motivated team that:

• Provides clients with unmatched value and absolute confidence
• Faithfully represents the interests of employees, clients and the public
• Earns recognition as the industry leader and benchmark in analytical expertise, quality, service and integrity

3. What certifications does EMLAB have?
We have been accredited by the American Industrial Hygiene Association's (AIHA) under their Environmental Microbiology Laboratory Accreditation Program (EMLAP. This program is designed specifically for laboratories specializing in analysis of microorganisms commonly detected in air, fluids and bulk samples as part of IAQ investigations. Since important health and financial decisions will be based on the results of these analyses, it is vital that the laboratory analyzing the samples be proficient in producing high quality data. The AIHA accreditation is one mark of this capability. In our view it is a necessary, but not sufficient, qualification for a laboratory.

We are also have been accredited by the California Environmental Laboratory Accreditation Program (CAL ELAP), which provides evaluation and accreditation of environmental testing laboratories to ensure the quality of analytical data used for regulatory purposes to meet the requirements of the State's food, drinking water, wastewater, shellfish, and hazardous waste programs. The State agencies, which monitor the environment, use the analytical data from these accredited laboratories. ELAP certified laboratories have demonstrated capability to analyze environmental samples using approved methods.

4. When samples are analyzed what kinds of information are available?
In most IAQ fungal investigations, three different types of samples are often taken.

1. Spore trap, or non-viable air samples.
2. Culturable air samples
3. Surface samples for direct microscopic examination

Each of these reveals different types of information and has strengths and weaknesses as outlined below, in addition to a summary of the basic technique.

A) Non culturable air samples Overview
Non-culturable spore trap samplers draw measured volumes of air through the sampling device for a specified length of time. The collection surface is a coated glass slide. Particles in the air (spores, dust, etc.) impact onto the sticky surface and are "trapped" for later analysis. Allergenco/Blewstone Press and Burkard Manufacturing both make spore trap sampling devices which accept standard glass slides which are greased by the user. Another company, Zefon Analytical Accessories manufactures disposable spore trap Air-O-Cell Cassettes. The primary advantage of Zefon's Air-O-Cell is their relatively low cost and small size (easy to transport, useful in small spaces). All of these devices have excellent aerodynamic characteristics and are very effective in monitoring airborne particles and organisms.

Our philosophy regarding the interpretation of biological air samples is formed primarily by two guiding principles. First, an effective interpretation is based on the comparison of indoor and outdoor samples. There are currently no guidelines or regulations to indicate "safe" or "normal" spore levels, however, we typically expect indoor counts to be 30 to 80 percent of outdoor spore counts, with the same general distribution of spore types present. And second, variation is an inherent part of biological air sampling. The presence or absence of a few genera in small numbers should not be considered abnormal.

Pros
Spore trap samplers are capable of capturing all spores and particulate matter in the air. Consequently, it is possible to accurately characterize problem environments where spores are present but either are no longer viable or are species that do not culture well (i.e. Stachybotrys). These are two situations where culturable sampling techniques, if used alone, may miss a potential IAQ problem.

Cons
While many mold spores have a unique morphology and are identifiable by direct microscopic examination, others do not and are more difficult to identify. These latter types must be counted in broader spore groups.

B) Culturable air samples Overview
Culturable sampling is one of the most common method of volumetric air sampling, and Andersen Instruments manufactures the most commonly used culturable sampling devices. The Andersen sampler works by drawing measured volumes of air through an instrument that contains a petri dish (or dishes) with culture media. Spores that impact onto the plate are then allowed to incubate and grow, after which the colonies may be counted and identified

Our philosophy regarding the interpretation of biological air samples is formed primarily by two guiding principles. First, an effective interpretation is based on the comparison of indoor and outdoor samples. There are currently no guidelines or regulations to indicate "safe" or "normal" spore levels, however, we typically expect indoor counts to be 30 to 80 percent of outdoor spore counts, with the same general distribution of spore types present. And second, variation is an inherent part of biological air sampling. The presence or absence of a few genera in small numbers should not be considered abnormal.

Pros
Culturable sampling allows for the differentiation of Aspergillus and Penicillium (speciation when required). It also provides counts indicative of how many spores are viable and present in the air. It can also be used to provide a bacterial count.

Cons
Culturable sampling methods require that the spores in the air are alive, survive the sampling process, germinate on the sampling media, and compete well with other species present on the growth media. Culturable sampling does not indicate the presence of non-viable spores, which may also be capable of producing allergies or irritation. Culturable sampling also requires five to seven days for incubation after the sampling has taken place.

C) Surface samples for direct microscopic examination Overview
There are other simple sampling methods that may be used to supplement volumetric air sampling. Surface samples are taken by tape lift imprint, by swabbing the suspect surface with a culturette swab, or by submitting a bulk sample of the suspect surface. We typically recommend that a direct microscopic examination be performed on surface samples. While culturing a surface sample may help resolve a specific identification problem, used alone such a culture may result in an inaccurate characterization of the surface sampled. A direct microscopic examination of a surface shows exactly what is there, without being affected by an organism's ability to compete and grow on sampling media

The primary purpose of a direct microscopic examination of a surface is to determine whether or not mold is growing on the surface sampled, and if so, what kinds of molds are present. Secondarily, most surfaces collect a mix of spores which are normally present in the environment. At times it is possible to note a skewing of the normal distribution of spore types, and also to note "marker" genera which may indicate indoor mold growth.

In addition, when mold growth is present indoors, many more spores of a particular type will be found trapped on surfaces. These spores may be in forms which indicate recent spore release (close proximity), such as spores in chains or clumps. Marker genera are those spore types which are present normally in very small numbers, but which multiply indoors when conditions are favorable for growth. These would include cellulose digestors such as Chaetomium, Stachybotrys, and Torula. While a single Stachybotrys spore is occasionally seen as part of the normal outdoor flora, finding 5 or 6 of these spores on a single scotch tape slide of a duct surface is an indicator that Stachybotrys may be growing indoors.

Pros
A direct microscopic examination of a surface shows exactly what is there, without any skewing by laboratory procedures. Surface sampling is inexpensive and (for a direct examination) may be analyzed immediately. Surface sampling may also reveal indoor reservoirs of spores which have not yet become airborne.

Cons
The presence of biological materials on a particular surface is not a direct indication of what may be in the air. Health problems related to indoor microbial growth are generally caused by the inhalation of substantial numbers of airborne spores, sometimes over a substantial period of time (exceptions being, for example, situations involving small children or immuno-compromised individuals).

I would like to conclude this answer by stating that 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 usuall the best choice when only one sampling method can be used.