Ohio Raises Cannabis Mold Limits — How It Compares to Michigan

What Changed in Ohio’s Cannabis Testing Rules?

Under Ohio’s original medical marijuana program — overseen at launch by the Ohio Medical Marijuana Control Program — total yeast and mold levels in flower were limited to 10,000 CFU/g.

Industry stakeholders argued the cap:

• Failed to distinguish between benign environmental microbes and dangerous pathogens

• Disproportionately impacted outdoor and greenhouse growers

• Increased batch failures without measurable public health benefit

The updated rules raise allowable yeast and mold thresholds, reducing the likelihood that cannabis flower will fail testing due solely to naturally occurring microbial presence.

Importantly, the revision does not eliminate safety screening.

Ohio still requires laboratory testing for:

• Salmonella

• Shiga toxin-producing E. coli

• Heavy metals

• Pesticides

• Residual solvents

The shift is less about lowering safety standards and more about refining them.

How Michigan’s Cannabis Testing Standards Differ

Across the state line, cannabis testing is overseen by the Michigan Cannabis Regulatory Agency (CRA), which employs a tiered microbial framework.

Michigan distinguishes between medical and adult-use cannabis:

• Medical cannabis: 10,000 CFU/g total yeast and mold limit

• Adult-use cannabis: 100,000 CFU/g limit

That means Michigan allows ten times more total mold and yeast in recreational flower compared to medical products.

But Michigan goes further in pathogen specificity.

The state mandates automatic failure if any of four Aspergillus species are detected:

• Aspergillus flavus

• Aspergillus fumigatus

• Aspergillus niger

• Aspergillus terreus

These fungi pose elevated risk to immunocompromised consumers, particularly medical patients.

Michigan’s framework therefore combines higher total microbial tolerance for adult-use products with strict zero-detection standards for high-risk pathogens.

Ohio’s rules emphasize total microbial thresholds but are less publicly explicit about species-specific automatic fails in summary documents.

Why This Matters to Growers and Retailers

Testing failures carry financial consequences.

When a batch fails microbial testing, operators may:

• Destroy the product

• Attempt remediation

• Pay for retesting

• Absorb lost revenue

In competitive cannabis markets, margins are already thin.

Michigan’s adult-use market has experienced prolonged price compression due to oversupply. Ohio operators are closely watching that dynamic as recreational sales expand.

By increasing allowable mold and yeast limits, Ohio may:

• Reduce product waste

• Lower compliance costs

• Improve supply stability

• Help moderate retail pricing

For multi-state operators active in both Michigan and Ohio, regulatory alignment reduces operational friction and compliance complexity.

Breakout Box: Ohio vs. Michigan at a Glance

Total Yeast & Mold (Flower)

• Ohio (previous cap): 10,000 CFU/g

• Michigan Medical: 10,000 CFU/g

• Michigan Adult-Use: 100,000 CFU/g

Pathogen Screening

• Michigan: Automatic fail for specific Aspergillus species

• Ohio: General microbial testing; fewer publicly specified pathogen lists

Market Impact

• Higher limits = fewer failed batches

• Fewer failed batches = lower waste + lower cost pressure

Consumer Safety vs. Economic Sustainability

The debate over microbial thresholds reflects a broader regulatory tension.

Set limits too low and states risk:

• Artificial supply shortages

• Elevated retail prices

• Incentives for illicit market purchases

Set limits too high and regulators risk:

• Public health concerns

• Loss of consumer trust

Michigan’s dual-tier system attempts to strike that balance. Ohio’s revision suggests regulators are now acknowledging similar economic realities.

The key public-health safeguard in both states remains targeted pathogen testing, not simply total mold counts.

A Sign of Regulatory Maturation

Early cannabis programs often adopt conservative safety limits. Over time, data from testing labs and industry experience drive adjustments.

Michigan went through similar recalibrations after launching adult-use sales in 2019.

Ohio’s decision signals that its cannabis regulatory environment is entering a more data-driven phase — balancing science, safety, and market sustainability.

For consumers, the practical takeaway is straightforward:

Products will still be tested.
Dangerous pathogens will still be screened.
But fewer batches will fail over naturally occurring microbial presence that does not present meaningful health risk.

For operators, the update offers breathing room.

For regulators, it reflects evolution.

Ohio’s raised mold and yeast limits move the state closer to Michigan’s adult-use tolerance model while maintaining laboratory oversight of harmful contaminants.

As Midwest cannabis markets mature, regulatory convergence appears underway — shaped by science, economics and competitive pressure.

Compliance still matters.
Safety still matters.
But sustainability now matters too.