A culturable sample, also called a viable sample, captures airborne or surface spores onto a growth medium so they can germinate into colonies a lab identifies and counts, reporting the result in colony-forming units per cubic meter.
What is a culturable sample?
A culturable sample answers a different question than a spore trap. Instead of counting every structure by microscopy, it grows only the spores that are alive and able to colonize the chosen agar, then identifies the resulting colonies, often to species, and reports colony-forming units (CFU). Because only viable, culturable spores show up, the count is almost always lower than a total-structure count from the same air, and the two cannot be read as fractions of each other (AIHA, Green Book). The trade is depth for completeness: you gain species-level identity and miss everything dead or slow to grow.
Why it matters to a mold inspection
Use a culturable method when species identity or viability is the actual question, not when you need a fast total-exposure snapshot. A culturable result undercounts, so reading a low CFU as "all clear" is a classic false negative: dead Stachybotrys spores still carry allergenic and inflammatory material and still matter, even though they never grow on a plate. Neither method maps to a pass/fail line, because the CDC states no acceptable airborne mold level has been established (CDC, About Mold). The full contrast is in spore trap vs culturable, explained and the spore trap vs culturable comparison.
MoldMind records the method on every sample, so a CFU/m3 culturable result and a spores/m3 trap result are never collapsed into one misleading narrative.
Try MoldMind free, 3 jobs, no card.
Sources
- CDC, About Mold: no established acceptable airborne mold level.
- AIHA, Green Book: viable vs non-viable sampling distinction and interpretation guidance.