How to Collect Physical Mold Growth Samples for Low-Cost Mold Laboratory Identification of Mold Species
VANCOUVER, CANADA. Many property owners, apartment landlords, renters, employers, and employees want to know, and need to know, the precise identities of the various mold species infesting their moldy house, rental unit, or place of employment, according to Phillip Fry, Certified Mold Inspector and author of the book Do-It-Best-Yourself Mold Prevention, Inspection, Testing, & Remediation.
The accurate identification of mold species requires two steps: (1) physical collection of mold samples from the moldy building; and (2) mold laboratory analysis of the collected mold samples.
The least costly way to collect mold samples is the do-it-yourself approach carried out by gathering actual samples of mold growth to submit for mold laboratory analysis ($20.00 or more fee per sample analyzed).
Bulk Physical Mold Sampling
If a property owner or occupant sees mold growing on a wall, ceiling, floor, heating or cooling duct register, or any other surface, he can scrape mold particles off the mold growth area into a small ziplock bag. Collecting such a physical sample is “bulk mold sampling” or “physical mold sampling.”
During such scraping of the mold growth, the tester needs to wear rubber gloves and a full-face respirator mask with organic vapor filters (such as the 3M brand from a large hardware, home improvement, or safety store).
To do the scraping, use a new or thoroughly disinfected (with ethyl or rubbing alcohol) paint scraper. Disinfect the scraper after each individual sampling to remove any possible mold contaminants, and thus avoid mold cross-contamination in the sampling process from one source or location to another.
Print clearly and neatly on a large pressure sensitive label the property owner’s name, the property address, the precise test location at that address, the testing date, and the type of sampling method (“bulk sample”), along with the tester’s name and contact information.
The label should also include each individual test number, as listed on the mold chain of custody form, available free from the mold laboratory. Attach the label to the ziplock bag containing that respective, numbered mold sample.
Alternatively, the tester can scrape the mold particles directly into a mold test kit (Petri dish) to start the growing (“culturing”) of the mold sample. This “viable testing” growth process takes 5 to 7 days for accuracy in mold species identification.
The tester can then either watch the test kits for mold growth, or send the mold test kit to the mold lab immediately, or after the self-observation growth period.
Another bulk physical sampling technique is to cut out a small section (no larger than 2 inches by 2 inches) of a building material or home furnishing that contains significant mold growth. Then, put that cut piece into a small ziplock bag, or press firmly the moldy side down into a mold test kit. Follow the same labeling instructions explained above.
Examples of moldy materials from which bulk samples can be cut for mold lab analysis are wood timbers, drywall, plasterboard, wallpaper, ceiling tile, carpeting, padding, heating/cooling system filters, clothing, furniture upholstery, and any other favorite mold food.
Scotch® Brand Tape Lift Sampling
The easy steps involved in tape lift sampling to collect physical bulk mold samples are—
1. Cut a three-inch (3”) long strip of one-inch (1”) wide, transparent sticky tape, such as Scotch® Brand Tape.
2. While wearing rubber gloves and a breathing respirator mask (with organic vapor filters) from the local hardware or home improvement store, press the tape strip firmly (sticky side down) onto the visible mold growth or onto the surface being tested.
3. Remove (peel back) the tape from the surface.
4. Open up a small ziplock bag (a transparent, easily sealable plastic storage bag), and press lightly the lift tape sample sticky side onto the inside sidewall of the ziplock bag.