By Tom Hymes

Remediation in the cannabis industry has become an increasingly hot topic as the practice has expanded in legal markets throughout the country, and for good reason. Remediation is performed when a crop has already failed testing or is suspected of being so contaminated that it will fail. Of course, the actual magnitude of cannabis remediation is unknown because producers are not required to label products that have undergone remediation, but it is not very difficult to identify flower that has been treated via remediation.

That is because no matter the grower or strain, remediated flower all looks the same – hard, charred, and absent the innate aesthetic characteristics found in all properly grown and cured flower. Neither are the deficiencies subtle. I cannot prove it, but I am convinced that most (if not all) of the flower I have bought from legal dispensaries in my home state of Connecticut was remediated. I could be wrong, of course, but I have no idea how else to explain the uniformity of the hard, bland nugs that look, feel, smell, and taste nothing like the generally sublime small-batch California flower I had become accustomed to smoking before moving back east.

But aesthetics and cultivation practices aside, the rationale for permitting remediation – that it makes products safe for consumption – has been generally accepted by regulators who permit the practice on the belief that there is no residual harm created by remediation. But what if that assumption is incorrect, and remediation does present a potential threat of injury to the same vulnerable populations that are told these products are safe to consume? Recent research by Beverly, Massachusetts-based Medicinal Genomics suggests that the potential for harm as a result of high levels of post-remediation endotoxins is real and requires further research. The topic – “Endotoxins in Cannabis Microbial Testing” – will also be the subject of a presentation next month at #CannMed24 by Medicinal Genomics founder and Chief Science Officer, Kevin McKernan.

The presentation will presumably build on results from the study released in late December that assessed “High levels of endotoxins in commercial cannabis flower.” A follow-up article in July, which tied the genesis of the study to tragic real-world events, posed an inevitable question to readers: “Should the Cannabis Industry Be Concerned About Endotoxins?”

“Employees in cannabis production facilities are exposed to large quantities of ground product, which may trigger asthma, allergic rhinitis, and urticaria,” began the article. “In November 2023, the CDC reported a fatal occupational asthma attack suffered by an employee at a Massachusetts cannabis production facility.

“The subsequent investigation did not determine a definitive cause for the condition,” it added. “However, the report did mention investigators tested the air for levels of endotoxin, ‘a pro-inflammatory contaminant associated with gram-negative bacterial growth on organic materials such as cannabis flower.’

“This piqued our interest,” it continued. “As a provider of cannabis pathogen testing technology, we understand that as much as 40% of bacteria found on cannabis flower are gram-negative bacteria capable of producing endotoxin. Yet, there are currently no regulations requiring endotoxin testing on cannabis. On the other hand, mycotoxin testing in cannabis is required in some jurisdictions.

“We also know that there is a growing number of cannabis cultivators who are using remediation techniques (irradiation, ozone treatment, acid treatment, hydrogen peroxide treatment, etc.) to reduce microbial load on cannabis material and pass compliance testing. This left us with the following questions:

• How much endotoxin is present on store-bought cannabis flower?
• Could remediation techniques mask the problem?
• Are endotoxins harmful to cannabis consumers?”

The study undertook to answer those questions. It was also the first survey of endotoxin levels on commercial cannabis flowers, according to the company.

“We report the presence of Endotoxin in high and low CFU/g cannabis flower samples,” noted the study abstract. “In some jurisdictions, cannabis samples over 100,000 CFU/g of total aerobic count, are prioritized for decontamination using ozone, E-beam, X-ray, or gamma ray exposure. While these methods are well known for reducing viable colony forming units, they are less effective at removing the DNA or endotoxin. Less is known about the residual endotoxin levels that might exist on such decontaminated products.

“To estimate this, we evaluated endotoxin levels of hemp samples in Massachusetts that are not subject to microbial testing and compared those to store-bought cannabis flower that must pass 100,000 CFU/g limits in Total Aerobic Count testing,” it continued. “We find significant levels (over 500EU/g) of endotoxin on all pre-rolls tested, regardless of CFU/g microbial testing requirements. Endotoxins on inhaled products can trigger asthmatic attacks. In light of a recent asthmatic fatality in a Massachusetts pre-roll facility, further scrutiny of decontamination procedures and their resulting endotoxin levels is required.”

Qualifications

A Discussion section of the findings added the following caveats. “Mycotoxin testing in cannabis is required testing in some jurisdictions,” it stated. “It is not currently known how much of these endotoxins survive vaporization or combustion. It is not known if the lower CFU/g in store-bought cannabis flower utilized a decontamination or remediation process as current labeling doesn’t require disclosure of these techniques in the state of Massachusetts. Prior studies investigating ozone remediation of endotoxin in water sources demonstrate a worsening of inflammatory potential at lower doses and a reduction of inflammatory potential at higher doses. The literature on the impact of various decontamination or remediation treatments on Cannabis flower derived endotoxin is non-existent and requires further study.

“Given the recent CDC inquiry into this cannabis employees fatality and its focus on airborne endotoxin levels,” it added, “we believe endotoxins are an overlooked risk to asthmatic patients. The endotoxin levels detected on these samples are orders of magnitude higher than the 90EU/m^3 airborne limits recommended by DECOS.”

The samples did vary, however. “In this study, many of the dispensary based samples were lower in CFU and 1-2 orders of magnitude lower in endotoxin levels, however 91 Octane was a clear exception,” stated the study. “This sample had low CFU by plating but exhibited clear signs of remediation with a large difference in live-dead qPCR as measured with before and after nuclease treatment qPCR.

“This is indicative of decontamination or remediation methods being adequate to produce passing CFU/g samples while leaving the endotoxin risk unaddressed,” it added. “This also leaves a live-dead DNA delta CT signature in its wake. Given the prevalence of endotoxin on cannabis in this study and the widespread use of cannabis without immediate adverse events for all users, endotoxin risk may only manifest itself in patients with compounding predispositions like asthma.”

The study also noted that a “more recent unappreciated environmental predisposition is the spike protein in SARs-CoV-2 which has been extensively published to exacerbate endotoxin stimulated hyperinflammation. This spike protein exists in both the virus and most SARs-CoV-2 vaccines. The Massachusetts fatality did occur during the pandemic period and employers larger than 100 employees were subject to federal vaccine mandates. It is not known to these authors if either of these confounders [affected] this case. Nevertheless, we believe these environmental amplifiers of endotoxin risk should be considered in the case of rare unexplainable fatal events. This is important to underscore as Cannabidiol has been published as a tool to reduce SARs-CoV-2 viral load via oral ingestion of high levels of CBD oil. Inhalation of high cannabidiol content cannabis may deliver the reverse effect if high levels of endotoxin are co-administered.”

The conclusion of the study was, as follows:

“Endotoxin is easily detected on a $6,610 portable fluorometer with 1 hour assay for under $10 per sample. This is one of the most affordable tests one could run in a cannabis testing lab. A recent fatal asthma case was documented in a Massachusetts pre-roll facility. The CDC has explored airborne endotoxin levels in this facility.

“This suggests endotoxin levels need to be explored on cannabis flower samples currently on the market. High levels (~100-1000X of the DECOS limits) of endotoxin were detected on both high and low CFU/g cannabis samples. This implies methods that rely solely on viable CFUs will be blind to endotoxin risk and that decontamination or remediation tools designed to eliminate viable bacteria, do not address all clinical risks present on the plant.

“Quantitative PCR methods that assess live-dead DNA have a slight correlation (0.43) with endotoxin EU/g. Knowledge of the decontamination and remediation methods used on every sample in Massachusetts may further refine these data and improve this correlation.”

The study also lists a sole conflict of interest: “The authors of this study are employed by Medicinal Genomics which manufactures the qPCR reagents used in this study.”

It is hard to see this issue vanishing outright in light of the presence of high levels of endotoxins found in commercial cannabis, and the potential they have to disproportionately impact medical cannabis patients who may be more susceptible to asthma than other cannabis consumers. At the very least, it is an issue that could (and probably should) inspire a very serious conversation about requiring remediated products to be labeled as such.