Mycotoxins Aren't Alive: Killing Mold Isn't the Same as Removing What It Produced

By Ken Fry, Terps USA Research — sourced from Terps USA Research

Short answer

Mycotoxins are chemical metabolites produced by certain fungi. They are not living organisms, so a process that reduces or inactivates viable mold is not automatically a process that removes toxins the mold produced earlier. That distinction matters because total yeast and mold count (TYMC) measures viable fungal burden; TYMC itself is not a mycotoxin assay, and testing requirements vary by jurisdiction.

The organism and its byproducts are two different problems

Some Aspergillus and Fusarium species can produce mycotoxins under the right conditions. Once those molecules exist, “killing the mold” and “removing the toxin” are separate questions. A microbial-control step can work exactly as intended against viable organisms without proving that every pre-formed metabolite has been eliminated.

Why remediation does not automatically erase the past

This distinction is not theoretical. Cannabis research has reported detectable mycotoxin residues even after treatment that reduced viable fungal counts. The useful conclusion is not that every remediation method fails, and not that every contaminated sample contains mycotoxins. It is that organism reduction and toxin removal require different evidence.

What TYMC does — and does not — tell you

TYMC is a measure of viable yeast and mold. It can be an important compliance and quality-control metric, but it is not designed to quantify mycotoxins. Some jurisdictions or testing programs may require separate toxin assays; others may not. A passing TYMC result therefore should not be described as proof that a sample is free of every fungal metabolite.

How common are mycotoxins in cannabis?

A 2025 study of seized cannabis samples from Arizona and California reported detectable mycotoxins in 16% of the samples tested, including Fusarium metabolites. That is an important signal, but the samples were seized products from two states and should not be treated as a prevalence estimate for all legal-market cannabis.

The prevention argument

The strongest practical lesson is simple: preventing fungal growth before toxins have an opportunity to form is a different strategy from trying to remediate the finished product afterward. That is the scientifically defensible reason prevention deserves attention — not because remediation never works, but because successful microbial control may not reverse everything that occurred before treatment.

FAQ

Can killing mold remove mycotoxins from cannabis?

Not necessarily. Mycotoxins are chemical metabolites, not living organisms. A process that reduces viable fungi does not by itself prove that pre-formed toxins have been removed or destroyed.

Does passing TYMC mean cannabis is free of mycotoxins?

No. TYMC measures viable yeast and mold; it is not itself a mycotoxin assay. Separate testing may be required depending on the jurisdiction or program.

How common are mycotoxins in cannabis?

A 2025 study of seized samples from Arizona and California found detectable mycotoxins in 16% of the samples tested. Because the sample set was seized cannabis from two states, that figure should not be generalized to all cannabis on the market.

Sources

1. Fry, K. (2026). "The DIY Decontamination Trap." Terps USA Research. DOI: 10.5281/zenodo.21115260

2. Leung, M., et al. (2025). Evaluation of Fusarium Mycotoxins and Fungal Metabolites in Seized Cannabis in Arizona and California, 2023-2024. Environmental Health Perspectives. DOI: 10.1289/EHP16028.

3. Gwinn, K.D., et al. Fungal and mycotoxin contaminants in cannabis and hemp flowers: implications for consumer health and directions for further research. Frontiers in Microbiology.

This article is for informational and industry education purposes only. Terps USA products do not contain THC or CBD. These statements have not been evaluated by the FDA. Readers are encouraged to consult the cited primary sources directly.