News Release

New study reveals high levels of fusarium mycotoxins in seized cannabis from Arizona and California

Peer-Reviewed Publication

Arizona State University

Seized cannabis may not be safe

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Seized cannabis. A new study found that 16% of the 118 samples tested positive for harmful mycotoxins, posing potential health risks to consumers. This groundbreaking research highlights the unregulated and dangerous nature of black-market cannabis.

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Credit: CDC

A recent study conducted by researchers from Arizona State University has uncovered alarming levels of Fusarium mycotoxins in illicit cannabis samples seized in Arizona and California.

 

The study found that 16% of the 118 samples tested positive for harmful mycotoxins, posing potential health risks to consumers. This groundbreaking research highlights the unregulated and dangerous nature of black-market cannabis.

 

The study, led by Arizona State University professor Maxwell Leung, analyzed cannabis samples obtained between November 2023 and June 2024 from law enforcement seizures. The samples were tested for 23 types of mycotoxins and fungal metabolites.

 

Notably, Fusarium mycotoxins such as fusarenon-X and diacetoxyscirpenol were present at levels exceeding regulatory standards for agricultural products. However, there are no federal or state monitoring or reporting programs for Fusarium contamination in legal and illegal cannabis.

 

“Many Fusarium mycotoxins can contribute to vomiting symptoms in users,” said Leung, an assistant professor in the School of Mathematical and Natural Sciences and study leader. “The presence of Fusarium fungi in cannabis can also pose an infection risk in immune-compromised users.”

 

Key Findings:

 

  • 16% of samples contained detectable levels of mycotoxins.

 

  • Fusarenon-X was found in 10 samples at concentrations ranging from 500 to 1,700 ppb, exceeding typical safety thresholds for food products.

 

  • Several samples contained diacetoxyscirpenol, a federally designated biological select agent and toxin, which presents a significant health concern.

 

  • In contrast, only one sample showed a regulated mycotoxin (ochratoxin A).

 

The research raises public health concerns, as many cannabis users may be unknowingly exposed to these dangerous fungal contaminants, which are linked to symptoms such as vomiting and gastrointestinal distress. Illicit cannabis, which is grown in unregulated environments, is particularly susceptible to contamination due to poor handling, unsanitary conditions, and lack of oversight.

 

Health Implications

Cannabis contaminated with Fusarium mycotoxins may pose serious health risks, particularly for individuals with weakened immune systems or those who consume cannabis for medicinal purposes. Mycotoxins such as fusarenon-X are known to cause vomiting, and their presence in cannabis could potentially exacerbate conditions like cannabis hyperemesis syndrome, which has been linked to increased emergency room visits.

 

While the legal cannabis market is subject to stringent safety testing, the black market remains a major source of unregulated and potentially dangerous products. In 2022, the illicit cannabis market in the U.S. was estimated to be worth $76 billion, more than double the size of the legal market, further emphasizing the public health risk posed by unregulated cannabis sales.

Needs for Future Research

The authors stress the urgent need for further research into the health risks associated with Fusarium contamination in cannabis, particularly regarding inhalation exposure through smoking or vaping, as well as dietary exposure through edibles.

“Despite the legalization effort at the state level, the majority of the cannabis supply remains coming from the black and grey market,” said Leung. “The contaminants in illicit cannabis represent a public health risk that needs to be addressed.”

For more information, the full study, "Evaluation of Fusarium Mycotoxins and Fungal Metabolites in Seized Cannabis in Arizona and California, 2023-2024," can be accessed through Environmental Health Perspectives (DOI 10.1289/EHP16028).


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