By Kristina Etter, Cannabis Tech

Aspergillus mold is all around us. According to the CDC, most people inhale a few Aspergillus spores daily without getting sick. However, of the approximately 180 species of Aspergillus, 40 of them can cause infections in humans. While most people have robust immune systems to help prevent aspergillosis infection, many medical cannabis patients may have pre-existing conditions which make them at risk for a potentially deadly fungal infection.


We asked Jill Ellsworth, founder and CEO of Willow Industries, to elaborate on why Aspergillus testing is critical for the consumer. She answered, “because of the dangers of inhaling Aspergillus and what it can do to the human body, it goes right into that delicate lung tissue and can have many negative health implications.”

From the CDC webpage on Aspergillus, there are multiple infections caused by inhaling this mold:

  • Allergic bronchopulmonary aspergillosis (ABPA)
  • Allergic Aspergillus sinusitis
  • Azole-Resistant Aspergillus fumigatus
  • Aspergilloma (or fungus ball)
  • Chronic pulmonary aspergillosis
  • Invasive aspergillosis

These infections can cause difficulty breathing, wheezing, cough, and fatigue. Aspergillus has already been documented as a severe medical complication for several medical cannabis patients.

Risk Factors

Young, healthy immune systems constantly fight off infection from foreign invasions of viruses, bacteria, and fungal infections. But, as we age or become immunosuppressed, the immune system’s ability to fight off these attacks fades, and we become more susceptible to disease.

As more people turn to medical cannabis, especially with the number of senior cannabis consumers on the rise, so is the risk of exposure to these harmful contaminants.

In a separate interview, Milan Patel, CEO of PathogenDX, added, “The United States has anywhere between seven and ten percent immunocompromised people living in the country – that’s up to 30 million people that have some level of a pre-existing condition.”

Patel also mentioned, “Around 110 labs use our technology across two to three dozen states. And we see anywhere from four to six percent of products with the different Aspergillus species.”

Now, it’s more important than ever to ensure consumer safety and reduce exposure to harmful contaminants such as aspergillus.


Similar to other states, until July 1st of this year, Colorado only had mandatory testing for total yeast and molds – there was no designation for Aspergillus specifically, similar to the requirements for bacteria like E. Coli and salmonella. 

Ellsworth commented, “It’s important that Colorado implemented this testing but also that we start to see this testing consistency throughout the U.S. [Right now] each state is bifurcated and siloed, but it’s nice to see consistency across the board in terms of testing regulations.”

Willow Industries recently published an interactive regulatory map to show the various microbial contaminant testing requirements from one state to the next. Most states are taking an aggressive stance against Aspergillus, with the standard set at 1 CFU per gram or less.

“If there’s one single colony of Aspergillus in that one gram of cannabis flower, it fails – it’s the same federal standards for food,” Patel explained.


Naturally, cannabis business owners likely took a deep breath as this new requirement took effect. Testing isn’t cheap, and cannabis businesses can’t write off their expenses. So, many businesses see this as another expense that increases their production costs and reduces their profits.

Patel stated, “that could be the biggest risk in my mind because if prices are dropping and costs are going up, it will drive the wrong behavior in Colorado.”

However, Jill Ellsworth warns, “The regulations are not going to get lighter once Federal regulations step in.” As the former owner of a cold-pressed juice company, Ellsworth is no stranger to the stringent requirements of the FDA. “There was no wiggle room in the requirements and processes to ensure our products were safe.”


While contaminant testing requirements may become more stringent as the industry grows, new allowances for remediation offer alternatives to losing entire crops.

Effective as of May 1st of 2021, Rule 4-135(C) allows for repeated attempts at decontamination of Harvest Batches of flower, shake, kief, and trim that have failed microbial testing. After decontamination, all batches must pass two microbial contaminant retests, water activity, and a mycotoxin test. 

Ellsworth explained that there are several methods for decontaminating and/or remediating a cannabis crop, but she also warns that these technologies have limitations. “If the product is incredibly contaminated, maybe it has black mold or bud rot, we don’t recommend even attempting to clean it,” she stated.

Willow Industries’ solution uses ozone to decontaminate cannabis, and Ellsworth added, “We really champion for a kill step. We want cultivators to do this preventatively as a standard part of the SOPS.”

“Other remediating technologies include radiation, radio frequency, and vaporized hydrogen peroxide, so it’s really up to the cultivator to research and determine the best solution for their operation,” Ellsworth advised.


Patel points out the obvious by asking, “Would you continue to eat moldy bread from now to the end of your living days?”

Awareness and education are critical. “Over the span of the next ten, twenty, or thirty years, when much of our populace consumes this, we must continue to drive awareness that [cannabis] should always be about safety and the health of the products,” Patel added.

Ellsworth also reminds us that big box stores, such as Walgreens, CVS, and Wal-Mart, aren’t going to allow products on their shelves without the necessary checks and balances. Just as there are standards for producing the foods we buy in the grocery store, there will always be regulations for those profiting from cannabis.

If your state isn’t calling for Aspergillus testing, chances are good they will be in the near future.