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Choosing a mold testing laboratory that is right for you

Mold testing professionals and other users should consider several factors in choosing a mold testing laboratory. This article refers to laboratories that specializes in identification and enumeration of mold and bacteria commonly detected in air, fluids and bulk samples collected from homes, schools, offices, hospitals, industrial, agricultural, and other work environments. Mold testing laboratories are generally not regulated by provincial or federal agencies. Consequently, it is important for mold testing professionals to investigate these laboratories by obtaining information about their performance, operation, and service before sending mold samples for analysis. A mold testing professional requires assurance that the test results will be of quality, be credible, and meaningful. Specific guidelines are discussed here to aid the mold testing professional in evaluating a mold testing laboratory.

Factors to Consider
Test Methods – The use of appropriate test methods is very important in order to accurately identify and/or enumerate mold spores or colony forming units (CFU) in an air sample.

Laboratory Proficiency – The proficiency of a mold testing laboratory refers to its ability to produce accurate and precise test results. It is difficult for a laboratory to independently assess this factor. Thus, reputable labs participate in AIHA sponsored EMPAT program. The Environmental Microbiology Proficiency Analytical Testing (EMPAT) Program is a voluntary performance evaluation program, administered by the American Industrial Hygiene Association (AIHA), for environmental microbiology laboratories. A main purpose of the EMPAT is to provide proficiency testing samples to laboratories who wish to monitor and improve the quality of their mold testing data. Participating laboratories receive a summary of their performance for each field of testing (FoT). Continued self-evaluation and adjustment improves the integrity of the mold test results. A prospective client should ask the laboratory management if they are members of the EMPAT program.

Laboratory’s EMPAT Results – It is important that a representative of the mold testing laboratory review with the potential client their EMPAT quarterly test results with those summarized for all EMPAT participating laboratories. Information for each FoT of interest to the client should be included. Mold testing professionals should ask for this comparison in order to make a good decision about a laboratory. Some laboratories that participate in the EMPAT program are not proficient.

Other Customers – The potential client should ask the mold testing laboratory to provide the names and telephone numbers of some customers. This allows the mold testing professional to evaluate the laboratory from the perspective of users like themselves.

Laboratory Results – Ask a laboratory representative for copies of sample results and ask them to explain the meaning of the units if they are unclear.

Turn-Around Time – Ask how long it takes the mold testing laboratory to do the routine mold testing and return the results. In order for the results and recommendations to be useful, the turn-around time must be as short as possible. A good laboratory should be able to provide the results in two to three working days for the routine mold tests of direct microscopic examination. It is also very important to make sure the laboratory does not sacrifice accuracy by short cutting the methods to attain this turn-around time. It is a good idea to check the turn-around time with those who have used the laboratory.

Visiting the Laboratory – Where possible, it is important to visit the mold testing laboratory before submitting samples. A representative of the laboratory should not hesitate to show a potential client the testing area. During the visit, observe the orderliness and cleanliness of the work area. Ask how the samples are handled. In addition, ask how the data is handled and ask about quality control that is used.

Sampling Supplies – Most mold testing laboratories supply test media such as agar, air-0-cells, and swabs to their customers. Find out about the supplies and how they are obtained from the laboratory.

Professionals Mycologists – Find out if the mold testing laboratory has professionals who are trained in mycology (the study of molds and yeasts) or microbiology to work with the customer. Before deciding on a mold testing laboratory, visit the laboratory and meet with a professional to discuss concerns about testing mold. When visiting a mold testing laboratory, ask to review the educational credentials of the professionals. Find out about the training background of the analysts.

Laboratory Test Prices – Prices for mold testing often vary greatly from one laboratory to the next. Ask about the prices. Determine if the price for each test or test package is given in writing. Also find out if discounts are given for large numbers of samples and whether prices are negotiable.

If you’re looking for a mold testing laboratory, please call 905-290-9101.

Legionella: Health Effects, Occurrence and Sampling

Health effects of Legionella

In 1976, in Philadelphia, USA, over 200 attendees of the US-American Legion, developed pneumonia. The disease was later called “Legionnaires’ disease”. The causative agent, a Gram-negative bacterium, was named Legionella pneumophila. Legionella pneumophila causes 85-90% of all cases of Legionella infections (legionellosis). There are over 40 species of Legionella.

Legionella pneumophila can cause very severe infection of the respiratory system. However, Legionnaires’ disease epidemics are rare but the disease is fatal if untreated. The disease may develop within 2 to 13 days (average 5-6 days).

Another form of legionellosis is Pontiac fever, named after an outbreak in 1968 in Pontiac, USA. This form of disease, caused by a number of Legionella species, is milder than Legionnaires’ disease. Pontiac fever develops within 48 to 72 hours and the illness may clear in 2-5 days. No fatal cases have been reported in relation to Pontiac fever. This disease mainly appears as epidemics. Pontiac fever is believed to be a reaction to inhaled Legionella antigens rather than an infection.

Disease transmission

There is no evidence for transmission of legionellosis from person to person or by ingestion. Legionella infection occurs when people inhale the bacterium via fine water droplets as aerosols from the environment. Indoor transmission of legionellosis has been reported via contaminated hot water supplies in hospitals, hotels and other public buildings, respiratory therapy equipment, jacuzzis, spas and air-humidifiers.

Occurrence

Legionella bacteria are part of the natural aquatic bacterial population of lakes and rivers. They are present in all types of fresh water, including tap water. Legionella multiply in water, using other microorganisms like bacteria, algae and protozoa. Their concentration in fresh water is influenced mainly by the temperature. They are isolated more frequently and in higher concentrations from warm water (30 to 50 °C.). However, Legionella also survive at much lower temperatures indoors as well as outdoors. At temperatures above 60 °C Legionella can’t survive.

Sampling Of Legionella

Sampling of Legionella in indoor air or water on a routine basis is not recommended. However, sampling is recommended to:

  • determine the source of outbreaks of legionellosis
  • check the effectiveness of maintenance practices and control measures for hot water supplies and humidified ventilation systems
  • guarantee the safe use of hot water supplies and humidified ventilation systems.

When investigating the water services within a building for Legionella, the condition of pipes, the joining methods used, the presence of lagging, sources of heat, and the standard of protection afforded tanks should be noted, as well as disconnected fittings, ‘dead-ends’, and cross-connections with other services.Water Sampling
Water samples should be collected in sterile autoclavable plastic containers. The samples should be taken from:

  • the incoming supply;
  • tanks;
  • an outlet close to, but downstream of, each tank;
  • the distant point of each service;
  • the water entering and leaving any fitting under particular suspicion.

Surface Sampling
Using swabs, surface samples should be taken from shower heads, pipes and taps. Also, sludge, slime or sediments within building water services or humidifiers can also be collected, particularly where accumulation occurs.

Sample Handling and Storage
Samples should be stored at room temperature (20 ± 5 °C.) in the dark and should be processed within 2 days. That means the samples should be sent to the laboratory within 24 hours. It is also important to confirm with the lab that they have the necessary media before sampling is done.

Air sampling
The presence of Legionella in indoor air can be investigated using Reuter Centrifugal Sampler (RCS) or the Andersen sampler. Regardless of the sampler used, the recommended sampling agar at present is BCYE-agar.

References

  1. Flannigan, B., R.A. Samson, and J.D. Miller (Editors). Microorganisms in home and indoor work environments: diversity, health impacts, investigation and control. 2001. London, UK: Taylor & Francis (ISBN: 0-415-26800-1).
  2. Wanner, H-U, AP Verhoeff, A Colombi, B Flannigan, S Gravesen, A Mouilleseux, A Nevalainen, J Papadakis, and K Seidel. 1993. Biological Particles in Indoor Environments. Indoor Air Quality and Its Impact On Man. Brussels: Commission of the European Communities. Report No. 12.

For more information on indoor bacteria, please visit http://www.moldbacteria.com/ or call 905-290-101.

Bacteria in the Water: Coliforms, Iron and Sulfur Bacteria

In the past we’ve discussed Legionnaires’ disease, which is a disease caused by a waterborne bacterium. In our September newsletter entitled, Bacteria in the Water: Coliforms, Iron and Sulfur Bacteria, we have discussed three types of waterborne bacteria: coliforms, which, although not usually harmful, can be a sign of other bacteria that are harmful; and iron and sulfur bacteria, which are seen as annoyances rather than a health threat. For more details read our Bacteria in Water: Coliforms, Iron and Sulfur Bacteria.

If interested in bacteria testing, visit the web page Testing For Bacteria or call 905-290-9101.

Salmonella food poisoning and symptoms

Salmonella food poisoning has been a growing concern in recent news. It has frequently lead to recalls of beef, salads and organic products and, even peanut butter products. Salmonella food poisoning occurs when one eats raw or undercooked foods such meat, poultry, eggs or egg products. Properly cooked food can get contaminated with Salmonella if […]

Legionella pneumophila – Guidelines for Laboratory Interpretation

Legionella pneumophila is a Gram negative, aerobic bacteria that is characterized as an opportunistic pathogen. It is the cause of Legionnaires’ Disease, a severe form of pneumonia and, it is the cause of Pontiac fever, a non-pneumonic form of L. pneumophila infection. Legionella spp.’s mode of transmission is through aerosols or aspiration of contaminated water. The Public Health […]

The Indoor Mold Is An Early Warning Device

The mold (or mould, in the Queen’s English) has been the victim of a bad press. Mention the word and it conjures up an image of something rotting or in the process of decomposition. And yet, were it not for the mold that inspired the discovery of penicillin millions of lives would have been lost. […]