A recent article from Cannabis Industry Journal raises a critical question that cultivators across the country should be asking: if water activity (aw) testing can predict microbial growth before it becomes a compliance failure, why aren’t more state regulators requiring it?
The Predictive Power of Water Activity
Water activity measures the amount of unbound water in cannabis flower available for microbial growth. Unlike moisture content, which simply tells you how much water is present, water activity indicates whether that environment can support mold and yeast proliferation. The science is well-established: cannabis flower with water activity below 0.60 aw is generally considered microbiologically stable, while levels above 0.65 aw create conditions where fungi can thrive.
Despite this knowledge, the Cannabis Industry Journal reports that many state cannabis programs still don’t include water activity in their mandatory testing panels. Cultivators are left testing for Total Yeast and Mold (TY&M) counts at the end of the production cycle—a reactive approach that catches contamination only after it’s already occurred.
Why This Matters for Cultivators
The implications of this regulatory gap are significant. Without water activity standards, cultivators may be curing and storing flower under conditions that silently encourage microbial growth. By the time product reaches final compliance testing, mold colonies may have already developed beyond acceptable limits. The result: failed batches, quarantined inventory, and potentially entire harvests headed for destruction rather than dispensary shelves.
Proper drying and curing protocols guided by water activity monitoring can dramatically reduce the risk of TY&M failures. However, even the most diligent operations face challenges. Variations in plant density, harvest timing, and environmental conditions during drying can create pockets of higher water activity within a batch. Outdoor and greenhouse cultivators face additional variables from weather and seasonal humidity shifts.
When Prevention Isn’t Enough
For cultivators who discover elevated TY&M counts despite their best preventive efforts, remediation becomes essential. Traditional approaches present difficult tradeoffs. Gamma irradiation effectively eliminates microbial contamination but raises concerns about product perception and potential degradation of sensitive compounds. Chemical treatments introduce residue risks and may affect the flower’s natural profile.
Cold plasma technology offers a different path. By generating reactive oxygen species that neutralize mold and bacteria on contact, cold plasma remediation achieves microbial reduction without chemicals, without irradiation, and without the heat that degrades THC and terpenes. The process treats flower in its final cured state, addressing contamination that developed during any stage of cultivation, harvest, or post-harvest handling.
A Two-Pronged Approach
The most resilient cultivation operations will likely adopt both strategies: implementing water activity monitoring as a preventive control point while maintaining access to effective remediation technology for batches that still fail compliance testing. As state regulations evolve—potentially incorporating water activity standards in the future—cultivators who understand both the science of prevention and the options for remediation will be best positioned to protect their harvests.
For operations exploring cold plasma remediation as part of their quality assurance toolkit, Curaflo provides systems specifically designed for cannabis flower at curaflo.tech.
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