July 26, 2023 | Dai Truong

We discuss recent headlines around product recalls and Aspergillus – and how Willow is helping cultivators prevent cannabis contamination to improve product safety and product quality.


  • How Jill Ellsworth developed a solution to clean cannabis contamination using ozone technology, and what challenges the company faced in finding the right technology and successfully gaining customers in the early days
  • Various methods of eliminating contaminants in cannabis
  • The challenges faced by cultivators and the importance of education and knowledge in mitigating contamination
  • Willow Industries’ lease revenue model, which offers cultivators a low upfront cost to deploy their solution and provides full-service support
  • Plans to expand internationally, particularly in Europe, where there is a need for alternative flower treatment methods due to regulations



  • The “kill step” is a point in manufacturing when dangerous pathogens are removed from the product, usually by killing them. It’s one of the most important steps in keeping products safe. While this is more prevalent in the agriculture and food and beverage industry, Willow Industries believes the cannabis industry should similarly adopt these standards for cannabis contamination
  • State regulators are still trying to figure out what microbes to guard against

Recent News: Cannabis Contamination

  • Recalls for contamination have become more prevalent. In June 2023, The Oregon Liquor Control Commission (OLCC) issued a recall for several batches of cannabis due to concerns of mold and heavy metals. According to the OLCC, more than nine batches of cannabis tested positive for the mold Aspergillus and heavy metals – cadmium and mercury. This includes cultivations owned by Nectarand Rebel Spirits
  • Oregon started testing for Aspergillus in April 2023, and previously had lax testing regulations. Cultivators had one year to comply but are currently struggling with the new requirements. The failure rate for flower has increased to 8% recently, from 6% in April
  • At least 22 other states require there to be no or very little aspergillus detected on cannabis. KOIN 6 found there are 16 states, including Washington and Puerto Rico, that don’t test for Aspergillus at all
  • In June 2023, Four Cannabis Products Recalled Due To Salmonella, Aspergillus Contamination In Arizona (Forbes). 
  • Phantom Farms in Nevada tested positive for Aspergillus (2News)

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