PLENNY LEARN · CONTAMINANT TESTING
Mold and its toxins are different findings
Mycotoxins are toxic substances made by certain molds. On a cannabis certificate of analysis (COA), look for a separate mycotoxin panel naming the toxins measured. A microbial result or a normal-looking sample does not replace that panel.
By Plenny · Updated September 19, 2026 · 4 minute read
What are mycotoxins in cannabis?
Mycotoxins are chemicals produced by some fungi, not the fungi themselves. The FDA’s mycotoxin overview explains that only certain molds produce these toxins. It identifies aflatoxins as products of certain Aspergillus molds and ochratoxin A as a product of certain Aspergillus and Penicillium molds.
The FDA source discusses food. It helps explain the terminology, but its food guidance is not a cannabis inhalation standard. For cannabis reporting, California’s testing overview lists microbial impurities and mycotoxins as separate test categories.
A microbial test evaluates the organisms specified by its method.
A mycotoxin test evaluates named chemical substances produced by certain molds.
Read both sections. One result does not supply the measurements missing from the other.
Aflatoxins and ochratoxin A on a cannabis COA
Look for aflatoxin B1, B2, G1 and G2, a combined aflatoxin result, and ochratoxin A. These are the substances addressed in section 15721 of California’s July 2026 regulations. That section treats the total of the four aflatoxins separately from ochratoxin A and requires results in micrograms per kilogram (µg/kg).
This is one program’s example, not a universal panel or limit for every hemp report. Find the actual specification attached to the COA.
Three examples to help read the results
Open each example. The numbers below are invented for arithmetic practice and do not certify a batch.
Example 1: four small results form one aflatoxin total
Suppose four quantified results, all in µg/kg, are B1 = 4, B2 = 3, G1 = 2 and G2 = 1.
4 + 3 + 2 + 1 = 10 µg/kg
The total is 10 µg/kg. Whether it meets a specification is a separate question. Use the lab’s official total and decision. If any component is ND or below a reporting threshold, ask how the laboratory handles that qualifier when calculating its total.
Example 2: one report uses ppb and another uses µg/kg
For mass-based concentrations, 1 µg/kg equals 1 part per billion (ppb). A fictional result of 10 µg/kg is therefore 10 ppb, not 10 ppm. The USDA Mycotoxin Handbook uses ppb for aflatoxin reporting.
Match the named toxin, units and reporting basis before comparing numbers from two reports.
Example 3: microbes passed, but no mycotoxin results appear
You have evidence for the microbial tests shown. You still need the mycotoxin panel to evaluate the listed toxins. Ask for the complete COA or clarification from the laboratory. Missing results establish neither a mycotoxin pass nor a failure.
A five-point mycotoxin report checklist
Use these boxes to organize your review. Selections are not saved and do not certify a product.
If a row is unclear, keep the question specific: “Does this total include B1, B2, G1 and G2?” or “What does ND mean under this method?” A precise question is more useful than assuming that every report uses the same conventions.
Common questions about cannabis mycotoxins
Can you see mycotoxins by looking at flower?
A visual check cannot measure toxin concentration. The USDA handbook, written for agricultural commodities, explains that the absence of visible mold does not assure the absence of toxins. A photograph cannot replace a laboratory result.
Does every mold produce mycotoxins?
No. The FDA distinguishes toxin-producing molds from molds generally. Finding a mold and measuring a particular toxin are different findings; neither should be invented from the other.
Does a mycotoxin pass mean all contaminants passed?
No. Pesticides, heavy metals and microbial impurities are separate categories in California’s testing overview. Read each relevant panel and the complete report rather than extending one result to every contaminant.
Can heating a suspect product prove it is safe?
No. Heating at home is not a laboratory test or a validated clearance procedure. The FDA’s animal-food guidance notes that ochratoxin A resists heat even though cooking can destroy many fungi. That does not establish what happens under every cannabis-use condition, and it does not support trying to salvage a suspect product.
Read the other contaminant panels
This guide explains report terminology. It cannot verify a particular batch or diagnose symptoms. If a product appears moldy or otherwise contaminated, stop using it and contact the supplier about the batch.
Chris Garcia, Owner and CEO
September 19, 2026
How this page is prepared: Plenny uses linked research and other relevant sources for educational explanations, and product details and batch COAs where relevant. General strain, flavor, and effect descriptions are not guarantees.
Commercial transparency: Plenny sells products discussed on this website. Educational pages are not medical or legal advice, and content is not medically reviewed unless a named licensed reviewer is shown.