As the legal landscape surrounding cannabis continues to evolve, the creation of robust, sensible and consistent safety regulations remains stalled. A patchwork of broadly inconsistent state rules and regulations, along with years of federal inaction and policy stagnation have the potential to create significant risks for consumers. Given the industry’s explosive, multi-billion-dollar growth, consumers have access to an ever-increasing number of products produced by an increasing number of actors, pursuant to widely divergent standards and rules. Given this, the industry would be well-served to take on the responsibility of promulgating a coherent regulatory framework with robust (but sensible) safety regulations. The importance of collaboration among cannabis industry stakeholders cannot be overstated if we are to develop and adopt consistent standards that guarantee product safety at every step of the supply chain.
To mitigate these risks, it is vitally important for the cannabis industry to collaborate in the ongoing development of safety standards. This means understanding and implementing safety measures starting with the cultivation process. Careful consideration should be given to factors such as the use of pesticides and herbicides, soil quality and irrigation methods. Standardized safety testing to ensure uniformity between products for potency, contaminants, heavy metals and microbial organisms is crucial to consumer safety. Accurate and comprehensive labeling is likewise necessary for consumers to be adequately informed.
For as long as consistent state and federal guidelines governing cannabis safety remain elusive, the need for industry self-regulation will be paramount. Cannabis companies must work together to share best practices, establish standard operating procedures and adopt stringent safety measures. By promoting transparency and collaboration, stakeholders can build credibility and consumer trust while fostering a safer and more reputable industry.
As the industry continues to grow, it is incumbent upon all stakeholders to continue prioritizing consumer safety through, among other things, a focus on education and inter-industry collaboration, if we are to continue cultivating a trustworthy and sustainable cannabis market for the future. The path forward will require stakeholders to pursue continuous education, improvement, and collaboration in the development of a holistic safety framework capable of ensuring consumer safety.
This is the fourth in a series of articles designed to introduce an integrated pest management framework for cannabis cultivation facilities. To see Part One, an overview of the plan and pest identification, click here. For Part Two, on pest monitoring and record keeping, click here. For Part Three, on preventative measures, click here. Part Five comes out next week on how to build a framework for control actions and how to monitor them. More to come!
This is Part 4: Direct Control Options
Even when the best methods are implemented and precautions are taken to protect your infrastructure, determined pests can penetrate your perimeter. Before you see crawling, hopping or flying insects, or sickly-looking plants, be sure to implement your physical protection (positive pressure airflow sealed facilities) and personal hygiene methods (shoe baths, sticky mats, & air shower entrances) to protect your crops. Equip your employees with personal protection equipment (PPE) proper gloves, masks and clothing as discussed in our last chapter, preventative measures.
Figure 1: Fungus Gnats Unleashed In A Grow Room
When things do break-out beyond your acceptable thresholds, Direct Control Options include non-chemical microbial biofungicides, microbial bioinsecticides and direct chemical control options. Lots of big scary words there, all of which are toxic even under safe application methods and when used at recommended concentrations levels. This means training in their use and protective clothing is required. Careful application of these control options is necessary so you exterminate your pests and not your people! This seems obvious, but do not just “wing it.”
These chemical elements can be applied in diluted concentration levels, manual wipe-down application, concentrated flush frequencies, or root drench applications, foliar spray mist applications, HVAC aerial diffusions and aerial knock-down sprays. You may even choose to remove badly infected plants and destroy them completely.
Use experts when you are planning for these tools. All of these methods require handling and safety precautions. Proper breathing filters, eye & skin protection, as well as disposable gowns/hazmat suits should be used when applications are performed and until the applications have dissipated to safe levels. Be careful not to co-mingle removed plant materials. Gloves become transport and infection spreaders after use.
Please also be sure to review your harvest testing requirements and what treatments are safe for your consumers and within legal limits. No one wants to have their harvest rejected due to pesticide contamination.
Figure 2: Municipal Water Treatment, RAIR Cannabis, Michigan
Clean-up after application may be required depending on the bioinsecticide or chemical that is used. Again, always ensure the safety of your employees and take precautions.
Start the application of your control options with your site map, room assignments and scout monitoring teams. Where does air flow into and within the facility? When your scouting team count logs go beyond your acceptable thresholds, here are some options for you.
Let’s begin with cleaning your irrigation and nutrient water sources. For a walk-through tutorial for incoming water treatment, humidity recovery and nutrient water recycling, please review the video tour of Water Treatment at RAIR Cannabis to see how an expert has done it.
From the IPM Planning Guide standpoint, peroxide and acid sterilizers can be used to clear irrigation water, for surface wipe-downs or as direct plant applications. We will cover those first. Caustic sterilizers require PPE for cleaning. Forgive my image here, we were just using water.
Plant interacting interfaces, i.e. surfaces, benches, walls, floors, trays, utensils, clippers, etc. should be sterilized with every use. Methods can include direct wipe-down or scrub, concentrated or diluted sprays or room vaporizers. A good example of hydrogen peroxide (H2O2) liquid would be a food grade sanitizer with 3-35% H2O2 content. Use acceptable diluted versions of these cleaners as appropriate.
Figure 3: Cleaning & Scrubbing, Where’s the PPE?
A commercial example would be Zerotol 2.0 with 27% H2O2 & their proprietary acid mix. Alternatively, you can use direct hydrogen peroxide generators from commercial sources to generate your H2O2 at various concentrations. More detailed examples are included in the complete Integrated Pest Management Guide (link at the end of this article). Establish your procedures for sterilizing your rooms and tools before you introduce plants, and describe what is to be done after every harvest and room turn. Track the cleaning materials used for your operational records. You will find this useful to track operational cost over time.
Sanitizing Acids for Surfaces & Irrigation Sources
Similar to hydrogen peroxide, hypochlorous acid (HOCl) comes in many commercial forms and can also be generated onsite using purchased generators. Commercial mix examples are UC Roots, Watermax and Athena Cleanse. They come in 0.028% to 15% concentrations. Self-generators range in output from highly precise 0.01% to 1% concentrations with more examples in the guide.
Treatment Tools
OK, so enough on cleaning preparation. Here are some tools that can be used to fight back against a pest intrusion:
Non-Chemical Microbial Biofungicide for Pathogens in Soil or Fertigation Water
Microbial fungicides are available to clear nutrient irrigation systems by minimizing pathogens and improving plant resistance to infections. Some fungicide versions target root pathogens by attacking the diseases directly. Others control or suppress common water carried challenges like pythium, rhizoctonia, phytophthora, fusarium and others. Brand names include Botanicare, Bonide, BioWorks, Actinovate, Mycostop and many more. Details covered in the guide.
Non-Chemical Microbial Bioinsecticides for Larval Stages
These biological tools attack the organisms or insects at a physical or mechanical way by breaking down the pest’s nervous system, biochemistry, or structural integrity (exoskeletons, etc.). These are engineered or living organisms (bugs to attack bugs) that are developed as targeted attacks for specific pests. Brand names are BioCeres, Botanigard, Venerate, Bio Solutions and others.
Minimal Risk Chemical Pesticides for Airborne Critters
Figure 3: Example Fungus Gnat Infestation – Royal Queen Seeds blog
Regularly approved for used in most locales, essential oils, natural acids (like citric acid) and insecticidal soap are commonly available in every hydroponic store. These work very well as safe spray “knock-down” insecticides for crawling or flying pests. Commercial examples use a proprietary mix of various oils, citric acids or isopropyl alcohol to do their task (examples in guide). Insecticidal soaps and fungicides for surface cleaning perform a similar purpose and typically use potassium salts or fatty acid mixtures.
Biochemical Pesticides
These tools are used to inhibit insect or fungal growth to acceptable levels. The multifaceted and commonly used neem oil comes in many commercial versions and is a naturally occurring pesticide extracted from the leaves and seeds of the neem tree. Example brand names are Bonide, Monterey, Triact and others. They range in concentrations from 0.9% to 70% concentrations. These oils suffocate living organisms or eliminate moisture to kill insects, spores or fungus at their initiation and throughout their lifespan.
Another option here are Azadirachtins. These act as insect growth regulators and disrupt the bugs natural evolution. Brand names are AzaGuard, AzaMax and others in the guide.
In summary, this week
We summarized some of the many pest control options available for water treatment, soil borne, intermediate or flying pests. We also covered various concentrations for these pesticide and sterilizer options. If you are not familiar with dilution ratios, %, PPM terms and how to apply the correct level of pesticide, you may find our plant science test kitchen blog on this topic of use here.
Chemical access and use should be restricted to employees familiar with their authorized application. PPE is very important to protect any employee that will come in contact with materials, liquids or vapors for chemical resources (gloves, boots, respirators, Tyvek (or equivalent protective wear) suits and eye protection or goggles.
For more detail on each of these treatments, you can see examples for your integrated pest management procedures in our complete white paper for Integrated Pest Management Recommendations, download the document here.
In our next chapter, Pest Population Control Actions, we will review control thresholds and example plans for a range of problems from biofilm build up to white flies and more. Our final chapter after that will suggest an emergency response framework and how to address pest outbreaks. See you next week.
Inexpensive in vitro Methods to Evaluate the Impact of Cannabinoid-containing Products on Sentinel Lactobacillus spp.
S. Lewin 1, A. Hilyard2, H. Piscatelli1, A. Hangman1, D. Petrik1, P. Miles2, and C. Orser2
1MatMaCorp Inc, Lincoln NE; 2Apothercare LLC, Boston MA
Abstract
The public has readily embraced cannabidiol (CBD) in countless unregulated products that benefit from commercial promotion without FDA oversight, who recently concluded: “that a new regulatory pathway for CBD is needed that balances individuals’ desire for access to CBD products w/ the regulatory oversight is needed to manage risks.”1 The reported antimicrobial properties of CBD combined with the recent proliferation of cannabinoid-containing products marketed to women for intimate care led us to explore the impact on the sentinel lactobacilli species associated with a healthy reproductive tract. Except for lubricants and tampons, the FDA regulates intimate care products as cosmetics. Even non-cannabis serums, washes, and suppositories are not required to be tested for their effect on the reproductive microbiota. We aimed to investigate the utility of easy-to-use, inexpensive in vitro assays for testing exogenous cannabis products on reproductive microbiota. In vitro assays can provide important evidence-based data to inform both manufacturers choosing both an active cannabinoid ingredient source as well as excipient chemicals and consumers in the absence of safety or quality data. In simple, straightforward exposure studies, we examined the antimicrobial activity of CBD and cannabigerol (CBG) on the most dominant vaginal lactobacilli species, L. crispatus, associated with good health.
Introduction
The testing of readily available products containing cannabinoids, predominately CBD following the widespread legalization of hemp by the 2018 US Farm Bill, is not required beyond ensuring THC content is below 0.3%. Therefore, basic information on safety, quality, antimicrobial activity, bioavailability, and dosing is unavailable and undocumented. The situation is further complicated by the complex chemoprofiles of cannabis extracts based on the cultivar, the extraction methods and subsequent cleanup, and other chemical excipients in the formulation. The FDA has finalized guidance on quality considerations for clinical research for the development of cannabis and cannabis-containing drugs intended for human use.
One approach to backfilling non-existent safety and quality data for cannabinoid active ingredients and those products made from them is to apply or devise assays that can provide relevant toxicity data in an in vitrosystem. Farha et al. (2020) reported that seven cannabinoids are potent antibiotics, including CBD and synthetic CBG. CBG inhibited the growth of gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), but not gram-negative bacteria unless their outer membrane was permeabilized (Farha et al. 2020). In addition, several volatile terpenes, the main constituents of essential oils extracted from Cannabis sativa L., also have potent antibiotic activity against gram-positive bacteria (Iseppi et al. 2019). We have previously written about the risks associated with disrupting the healthy microbiome of gram-positive vaginal bacterial species leading to dysbiosis (Orser 2022) and its further health complications.
Several successful approaches to assessing the toxicity of CBD have already been reported including human cell culture work by Torres et al. (2022) who showed that pure CBD has a repeatable impact on cell viability, but that hemp-derived finished CBD products had variable impact. Cultured human cell viability experiments demonstrated similar potencies across three different hemp-derived CBD products in the microgram per milliliter [mg/mL] range with increased viability at lower doses [2-4 mg/mL] and decreasing cell viability above 6 mg/mL (Torres et al. 2022). In the same study, the authors demonstrated that the presence of terpenes, specifically b-caryophyllene, in hemp extraction matrices also impacted cell viability.
Neswell, a cannabis therapeutics company in Israel, demonstrated through the application of their in vitroneutrophil cell line that cannabis extracts have inherent immune response biodiversity, suggesting that the choice of a cannabis source should be based on its function rather than on its chemoprofile (https://www.neswell.net). Inflammatory cytokine levels in inflamed peripheral blood mononuclear cells (PB_MC) showed a 10-fold difference across hemp extract products containing unidentified terpenes in suppressing the inflammatory cytokine, TNFa (Torres et al. 2022). The influence of CBD concentration on inflammatory cytokine production was previously reported by Vuolo et al. (2015) and Jiang et al. (2022).
Materials & Methods
Chemicals and Products Tested
THC-free, 99% pure CBD and CBG isolates were purchased from Open Book extracts in North Carolina (openbookextracts.com). All other chemicals including erythromycin (EM), and growth media were obtained from Sigma-Aldrich (St. Louis MO). Specific reagents in the qPCR kits were assembled in-house at MatMaCorp Inc. (Lincoln NE).
Monitoring Cell Viability: OD600nm and plating
Individual frozen glycerin stocks of L. crispatus HM103 from BEI Resources Repository served as inoculum to streak on a sterile MRS agar plate and incubated anaerobically at 370C for 24-48 h until individual colony growth was observed. Single colonies were used to inoculate MRS broth and incubated for 24-48 h at 370C which served as the inoculum for exposure to test products. Exposed cultures and all control cultures were incubated at 370C for 48 h with OD600 readings taken at time zero, +24 h, and +48 h using disposable cuvettes in a standard spectrophotometer. The products were also plated onto MRS agar plates to evaluate inherent contaminants that could affect turbidity values.
Molecular Analysis by qPCR
DNA isolation from bacterial cultures was done using the MatMaCorp (Lincoln, NE) StickE Tissue DNA Isolation kit modified for bacteria as per manufacturer instructions. Briefly, a lysis buffer is applied to the sample followed by a heating step, and a binding buffer is added, thus allowing DNA from the solution to bind to the matrix of the StickE column. The column was washed prior to eluting the purified DNA. Per manufacturer instructions, 10 µL of isolated DNA was used as a template for genetic analysis in a Lacto-TM assay (MatMaCorp). The assay is a customized TaqMan-based detection assay that is conducted using a four-channel fluorescence detection platform, the Solas 8 (MatMaCorp). The assay was designed to detect the unique 16S-rRNA DNA sequence for L. crispatus. Briefly, the assay is a probe-based method that begins with hybridizing the custom-designed probes with their desired nucleic acid target found in the sample. Once hybridized, detection takes place from the fluorescently labeled primer. The target has been assigned a channelon the Solas 8 and is detected independently.
Calling the Results
The calling algorithm uses first-order kinetics reaction properties (inflection point detection) in combinationwith a measure of the closeness of the signals associated with a specific target. Various indicators are tracked during the reactions to perform an on-the-fly analysis. The analysis is then consolidated by a measure of the similarity between the fluorescence signals at the end of the run. Aggregating values from the similarity measure, the end gain and the inflection point detection allow the Solas 8 software to make the call at the end of the run without having to compare a results library of known sample targets.
Figure 1: qPCR Findings
Results
Exposure of L. crispatus
Anaerobically grown cultures of L. crispatus were exposed to either CBD isolate or CBG isolate at each of two concentrations [5 mg/mL] and [10 mg/mL] with all appropriate controls. All treatment groups were evaluated by qPCR, turbidity at OD600, and plate counts.
Molecular Analysis via qPCR
These data show the specificity of the Solas8 testing for evaluating these products, as a molecular-level screening is not influenced by test product solubility, opacity, or non-specific contamination present in some of the tested products that can interfere with optical density measurements.
Growth Monitoring
Figure 2: Turbidity
Turbidity monitoring, albeit non-specific, confirmed the species-specific qPCR findings, that is no inhibition for the two cannabinoid isolates evaluated (Fig. 2).
Conclusions
In this limited in vitro study using a sentinel lactobacilli response, we have shown that 99% pure CBD and CBG isolates were not inhibitory at the two doses evaluated by complementary observations following turbidity, plating, and by qPCR. Limitations in this study prevent definitive conclusions regarding what individual or combination of cannabinoids or other cannabis secondary metabolites are inhibitory in vivo to dominant lactobacilli species in the reproductive tract. These limitations include commercial product testing without knowledge of excipients or impact on the bioavailability of any active cannabinoid ingredients. In addition, dose-response curves were not generated and exposure under micro-aerobic conditions was not carried out.
Cannabidiol’s potential as an antimicrobial agent may be limited by its extremely low solubility in water and a propensity to stick to spurious proteins limiting systemic distribution in the body as a therapeutic. Interpreting microbiome study findings to human health outcomes will require multi-disciplinary corresponding clinical data findings of disease diagnosis, processes, and treatment within populations. Nonetheless, this nascent translational research opportunity is vast with the promise of benefiting patient outcomes (Wensel et al. 2022).
Health Canada released a scientific review report on products containing cannabis, specifically containing 98% or greater CBD and less than 1% of THC (Health Canada 2022) while the FDA just concluded that there are no existing guidelines applicable for recommending safety and quality guidelines to manage risk for CBD products (U.S. FDA 2023). The Health Canada committee unanimously agreed that short-term use of CBD is safe at 20 mg per day up to a maximum dose of 200 mg per day and that packaging should include both dosing instructions and potential side effects. The Committee did not address the antimicrobial potential of CBD or CBG formulations or specifically vulvar or vaginally administered cannabinoids. There is clearly more basic physiological research needed on the impact of self-administration of CBD preparations based on the route of exposure.
Hopkins AL (2008) Network pharmacology: the next paradigm in drug discovery. Nat Chem Biol 4(11):682-90.
Iseppi R, Brighenti V, Licata M, Lambertini A, Sabia C, Messi P, Pellati F, Benvenuti S (2019) Chemical characterization and evaluation of the antibacterial activity of essential oils from fibre-type Cannabis sativa L. (Hemp) Molecules 24:2302; doi:10.3390/molecules24122302.
Jiang Z, Jin S, Fan X, Cao K, Liu Y, Want X, Ma Y, Xiang L (2022) Cannabidiol inhibits inflammation induced by Cutibacterium acnes-derived extracellular vesicles via activation of CB2 receptor in keratinocytes. J Inflammation Res 15:4573-4583.
Torres AR, Caldwell VD, Morris S, Lyon R (2022) Human cells can be used to study cannabinoid dosage and inflammatory cytokine responses. Cannabis Sci & Tech 5(2) 38-45).
U.S. FDA (2023) https://www.fda.gov/news-events/press-announcements/fda-concludes-existing-regulatory-frameworks-foods-and-supplements-are-not-appropriate-cannabidiol
Vuolo F, Petronilho F, Sonai B, Ritter C, Hallak JE, Zuardi AW, Crippa JA, Dal-Pizzol F (2015) Mediators Inflamm 538670
Wensel CR, Salzberg SL, Sears CL (2022) Next-generation sequencing insights to advance clinical investigations of the microbiome. J Clin Invest 132(7):e154944. https://doi.org/10.1172/JCI154944.
Cannabis testing to detect microbial contamination is complicated. It may not be rocket science, but it is life science, which means it’s a moving target, or at least, it should be, as we acquire more and more information about how the world we live in works. We are lucky to be able to carry out that examination in ever increasing detail. For instance, the science of genomics1 was born over 80 years ago, and just twenty years ago, genetics was still a black box. We’ve made tremendous progress since those early days, but we still have a long way to go, to be sure.
Much of that progress is due to our ability to build more accurate tools, a technological ladder, if you will, that raises our awareness, expertise, and knowledge to new levels. When a new process or technology appears, we compare it against accepted practice to create a new paradigm and make the necessary adjustments. But people have to be willing to change. In the cannabis industry, rapid change is a constant, first because that is the nature of a nascent industry, and second because in the absence of some universal and unimpeachable standard, it’s difficult to know who’s right. Especially when the old, reliable reference method (i.e. plating, which is basically growing microorganisms on the surface of a nutritional medium) is deeply flawed in its application to cannabis testing vs. molecular methods (i.e., quantitative polymerase chain reaction, or qPCR for short).
Dr. Sherman Hom, Director of Regulatory Affairs at Medicinal Genomics
Plating systems have been used faithfully for close to 130 years in the food industry, and has performed reasonably well.2 But cannabis isn’t food and can’t be tested as if it were. In fact, plating methods have a host of major disadvantages that only show up when they’re used to detect cannabis pathogens. They are, in no particular order:
A single plating system can’t enumerate a group of microorganisms and/or detect specific bacterial and fungal pathogens. This is further complicated by the fact that better than 98% of the microbes in the world do not form colonies.3 And there is no ONE UNIVERSAL bacterial or fungal SELECTIVE agar plate that will allow the growth of all bacteria or all fungal strains. For example, the 5 genus species of fungal strains implicated in powderly mildew DO NOT plate at all.
Cannabinoids, which can represent 10-30% of a cannabis flower’s weight, have been shown to have antibacterial activity.4 Antibiotics inhibit the growth of bacteria and in some cases kill it altogether. Salmonella species & shiga toxin producing coli (STEC) bacteria, in particular, are very sensitive to antibiotics, which leads to either a false negative result or lower total counts on plates vs. qPCR methods.
Plating methods cannot detect bacterial and fungal endophytes that live a part or all of their life cycle inside a cannabis plant.5,6 Examples of endophytes are the Aspergillus pathogens (A. flavus, A. fumigatus, A. niger, and A. terreus). Methods to break open the plant cells to access these endophytes to prepare them for plating methods also lyse these microbial cells, thereby killing endophytic cells in the process. That’s why these endophytes will never form colonies, which leads to either false negative results or lower total counts on plates vs. qPCR methods.
Selective plating media for molds, such as Dichloran Rose-Bengal Chloramphenicol (DRBC) actually reduces mold growth—especially Aspergillus—by as much as 5-fold.This delivers false negative results for this dangerous human pathogen. In other words, although the DRBC medium is typically used to reduce bacteria; it comes at the cost of missing 5-fold more yeast and molds than Potato Dextrose Agar (PDA) + Chloramphenicol or molecular methods. These observations were derived from study results of the AOAC emergency response validation.7
Finally, we’ve recently identified four bacterial species, which are human pathogens associated with cannabis that do not grow at the plating system incubation temperature typically used.8 They are Aeromonas hydrophila, Pantoea agglomerans, Yersinia enterocolitica, and Rahnella aquatilis. This lowers total counts on plates qPCR methods.
So why is plating still so popular? Better yet, why is it still the recommended method for many state regulators? Beats me. But I can hazard a couple of guesses.
A yeast and mold plate test
First, research on cannabis has been restricted for the better part of the last 70 years, and it’s impossible to construct a body of scientific knowledge by keeping everyone in the dark. Ten years ago, as one of the first government-employed scientists to study cannabis, I was tapped to start the first cannabis testing lab at the New Jersey Dept. of Health and we had to build it from ground zero. Nobody knew anything about cannabis then.
Second, because of a shortage of cannabis-trained experts, members of many regulatory bodies come from the food industry—where they’ve used plating almost exclusively. So, when it comes time to draft cannabis microbial testing regulations, plating is the default method. After all, it worked for them before and they’re comfortable with recommending it for their state’s cannabis regulations.
Finally, there’s a certain amount of discomfort in not being right. Going into this completely new area—remember, the legal cannabis industry didn’t even exist 10 years ago—we human beings like to have a little certainty to fall back on. The trouble is, falling back on what we did before stifles badly needed progress. This is a case where, if you’re comfortable with your old methods and you’re sure of your results, you’re probably wrong.
So let’s accept the fact that we’re all in this uncharted territory together. We don’t yet know everything about cannabis we need to know, but we do know some things, and we already have some pretty good tools, based on real science, that happen to work really well. Let’s use them to help light our way.
References
J. Weissenbach. The rise of genomics. Comptes Rendu Biologies, 339 (7-8), 231-239 (2016).
R. Koch. 1882. Die Aetiologie der Tuberculose. Berliner Klinische Wochenschrift, 19, 221-230 (1882).
W. Wade. Unculturable bacteria—the uncharacterized organisms that cause oral infections. Journal of the Royal Society of Medicine, 95(2), 91-93 (2002).
J.A. Karas, L.J.M. Wong, O.K.A. Paulin, A. C. Mazeh, M.H. Hussein, J. Li, and T. Vekov. Antibiotics, 9(7), 406 (2020).
M. Taghinasab and S. Jabaji, Cannabis microbiome and the role of endophytes in modulating the production of secondary metabolites: an overview. Microorganisms 2020, 8, 355, 1-16 (2020).
P. Kusari, S. Kusari, M. Spiteller and O. Kayser, Endophytic fungi harbored in Cannabis sativa L.: diversity and potential as biocontrol agents against host plant-specific phytopathogens. Fungal Diversity 60, 137–151 (2013).
K. McKernan, Y. Helbert, L. Kane, N. Houde, L. Zhang, S. McLaughlin, Whole genome sequencing of colonies derived from cannabis flowers & the impact of media selection on benchmarking total yeast & mold detection tools, https://f1000research.com/articles/10-624 (2021).
K. McKernan, Y. Helbert, L. Kane, L. Zhang, N. Houde, A. Bennett, J. Silva, H. Ebling, and S. McLaughlin, Pathogenic Enterobacteriaceae require multiple culture temperatures for detection in Cannabis sativa L. OSF Preprints, https://osf.io/j3msk/, (2022)
In a press release published this week, AOAC International announced it has partnered with Signature Science, LLC as the test material provider for the new AOAC Cannabis/Hemp Proficiency Testing program. What makes this proficiency testing (PT) program so unique is that AOAC will be the only PT provider to offer actual cannabis flower as the matrix.
This month, the pilot round with twenty cannabis testing labs begins with hemp-only samples being shipped in early May. The first live round of the PT program is scheduled for November of this year and will offer participating labs the choice of cannabis flower samples or hemp samples.
The program will include one sample for cannabinoid and terpene profiles, moisture and heavy metals, as well as a second sample for pesticide residue testing. According to the press release, mycotoxins will be added to the mix soon.
The new PT program was developed by stakeholders involved with the AOAC Cannabis Analytical Science Program (CASP), including state regulatory labs, industry labs, state and federal agencies and accreditation bodies. Shane Flynn, senior director of AOAC’s PT program, says the program is a result of scientists coming to them with concerns about testing in the cannabis space. “AOAC has a long history of bringing scientists together to address emerging topics, so when stakeholders came to AOAC with their concerns and need for quality proficiency testing in the cannabis industry, AOAC acted,” says Flynn. “Stakeholders noted the analytical differences in testing cannabis versus hemp and had specific concerns around it and asked for a program that would provide actual cannabis samples in addition to hemp. This is truly a program that was created by the stakeholders, for the stakeholders.”
AOAC says they plan on introducing microbiology to the PT program, with microbial contamination tests in both cannabis and hemp samples. They are also considering adding additional matrices, like chocolate and gummies.
Signature Science is an ISO 17043 accredited proficiency test provider that also has a DEA-licensed controlled substances lab, making them an ideal candidate to partner with AOAC for the PT Program. They entered into a 3-year MoU with AOAC for the program. Their team developed and validated methods used to create the samples for the PT program at their DEA-licensed lab in Austin, Texas.
By Jill Ellsworth MS, RDN, Tess Eidem, Ph.D. No Comments
As an emerging field in cannabis, contaminant testing remains a gray area for many businesses. The vast differences in state-by-state regulations, along with the frequent changes of previously established rules make testing a difficult, time-consuming process. But at its core, the science and reasoning behind why we test cannabis is very clear – consumer safety and quality assurance are key factors in any legal, consumer market. The implications of federal legalization make cannabis testing even more important to the future of the cannabis supply chain. Understanding the types of contaminants, their sources and how to prevent them is essential to avoiding failures, recalls and risking consumer safety.
When talking about cannabis contaminant testing there are four groups of contaminants: pesticides, heavy metals, foreign materials and microbes. The microbes found on cannabis include plant pathogens, post-harvest spoiling microbes, allergens, toxin release and human pathogens. While all of these can be lurking on the surface of cannabis, the specific types that are tested for in each state vary widely. Understanding the full scope of contaminants and looking beyond state-specific compliance requirements, cultivators will be able to prevent these detrimental risks and prepare their business for the future.
Environmental controls are essential to monitor and regulate temperature and humidity
Beyond just the health of the plant, both medical patients and adult use consumers can be adversely affected by microbial contaminants. To immunocompromised patients, Aspergillus can be life-threatening and both adult use and medical consumers are susceptible to allergic reactions to moldy flower. But Aspergillus is just one of the many contaminants that are invisible to the human eye and can live on the plant’s surface. Several states have intensive testing regulations when it comes to the full breadth of possible harmful contaminants. Nevada, for example, has strict microbial testing requirements and, in addition to Aspergillus, the state tests for Salmonella, STEC, Enterobacteriaceae, coliforms and total yeast and mold. Over 15 states test for total yeast and mold and the thresholds vary from allowing less than 100,000 colony forming units to allowing less than 1,000 colony forming units. These microbes are not uncommon appearances on cannabis – in fact, they are ever-present – so understanding them as a whole, beyond regulatory standards is a certain way to future-proof a business. With such vast differences in accepted levels of contamination per state, the best preparation for the future and regulations coming down the pipeline is understanding contamination, addressing it at its source and harvesting disease-free cannabis.
The risk of contamination is present at every stage of the cultivation process and encompasses agricultural practices, manufacturing processes and their intersection. From cultivation to manufacturing, there are factors that can introduce contamination throughout the supply chain. A quality control infrastructure should be employed in a facility and checkpoints within the process to ensure aseptic operations.
Microbial monitoring methods can include frequent/consistent testing
Cultivators should test their raw materials, including growing substrates and nutrient water to ensure it is free of microbial contamination. Air quality plays an important role in the cultivation and post-harvest processes, especially with mold contamination. Environmental controls are essential to monitor and regulate temperature and humidity and ensure unwanted microbes cannot thrive and decrease the value of the product or make it unsafe for worker handling or consumers. Developing SOPs to validate contact surfaces are clean, using proper PPE and optimizing worker flow can all help to prevent cross-contamination and are part of larger quality assurance measures to prevent microbes from spreading across cultivars and harvests.
Methods of microbial examination include air quality surveillance, ATP surface and water monitoring, raw materials testing, and species identification. Keeping control of the environment that product is coming into contact with and employing best practices throughout will minimize the amount of contamination that is present before testing. The solution to avoiding worst case scenarios following an aseptic, quality controlled process is utilizing a safe, post-harvest kill-step, much like the methods used in the food and beverage industries with the oversight of the FDA.
The goal of the grower should be to grow clean and stay clean throughout the shelf life of the product. In order to do this, it is essential to understand the critical control points within the cultivation and post-harvest processes and implement proper kill-steps. However, if a product is heavily bio-burdened, there are methods to recover contaminated product including decontamination, remediation and destroying the product. These measures come with their own strengths and weaknesses and cannot replace the quality assurance programs developed by the manufacturer.
Risk management is the process of identifying potential hazards, assessing the associated risk, then implementing controls to mitigate those risks. With Salmonella and Aspergillus being two of the leading causes of cannabis contamination that can occur throughout the supply chain, applying upstream risk management strategies can keep supplier contamination issues from impacting your products.
Salmonella enteritidis
In recent months cannabis products have been recalled for Salmonella and/or Aspergillus contamination in several states, including California, Arizona, Michigan, Florida, as well as Canada. While the recalls impacted retail products, in most cases, the contamination occurred farther back in the supply chain, as evidenced by recalls that impacted several dispensaries or other sales locations.
For example, the November 2021 Arizona recall caused multiple establishments and dispensaries to recall product due to possible contamination with Salmonella or Aspergillus; the Michigan recall of an estimated $229 million in cannabis products due to “inaccurate and/or unreliable results of products tested.” While a lab lawsuit against the recall released some of the product to market, the companies faced significant impact – in both removing and returning the product.
While microbial contamination can occur throughout the supply chain, Aspergillus is ubiquitous in soil and the flower, leaves, roots of the cannabis plant are all susceptible to such contamination. The mold also can colonize the bud both during growing and harvesting. Salmonella can be introduced during growing through, untreated manures, direct contact with animal feces, or contamination of surface water used for irrigation. However, the plant matter also can be compromised during drying, storage and processing from environmental contamination.
Aspergillus flavus
Supply chain risk management. To prevent a supplier’s contamination issues from becoming your problem to deal with, each facility at each step of the chain should develop a supply chain risk management program to assess and approve each of its upstream providers. Following are 5 key steps to assessing and managing risk in your supply chain:
Conduct a hazard analysis. A complete supply chain assessment should begin with a hazard assessment of all the ingredients, products or primary packaging you receive. There are two essential steps involved in conducting a hazard analysis: that is the identification of potential hazards – considering those related to the item itself, as well as the supplier environment and process as well as item – and an evaluation to determine if each hazard requires control based on its severity and likely occurrence.
Evaluate the risks. Based on the hazard analysis, the next step is to determine the associated risk. As defined by the European Food Information Council (EUFIC), “a hazard is something that has the potential to cause harm while risk is the likelihood of harm taking place, based on exposure to that hazard.” For example, the higher the exposure, the higher the risk.
Ensure risk control. Once risk is determined, it is critical to ensure that it is being controlled, who is controlling it and how it is being done. Depending on the risk, that control may need to be conducted by the supplier, by you or even by a downstream customer.
Require documentation. No matter which step in the chain is controlling the risk, it is essential that all be documented with records easily accessible – including the controls, any out-of-compliance events and corrective actions. The adage, “If it’s not documented, it didn’t happen,” is very applicable here, particularly should a problem arise and an inspector appear at your door.
Use only approved suppliers. Implementation of the above steps enable the development of a supplier approval program focused on quality, safety and regulatory compliance. Use of only suppliers who have been assessed and found to meet all your standards will help to protect your product and your brand.
Salmonella and Aspergillus contamination can occur throughout the supply chain, but implementing a supply chain risk assessment and management program will enable you to determine where the greatest risks lie among your ingredients and suppliers, allowing you to allocate resources based on that risk.
Medicinal Genomics announced today that they have received AOAC International certification for their PathoSEEK® Salmonella and STEC E. coli multiplex assay. In combination with their SenSATIVAx® extraction kits, labs can simultaneously detect Salmonella spp. and STEC E. coli with a single qPCR reaction for flower, concentrates and infused chocolates using the Agilent AriaMx and the BioRad CFx-96 instruments.
The certification came after the multiplex assay was validated according to the AOAC Performance Tested Method Program. According to the press release, the PathoSEEK platform now has more cannabis matrices accredited for Aspergillus, Salmonella, and STEC E. coli than any other product out on the market, according to their press release.
The PathoSEEK microbiological testing platform uses a qPCR assay and internal plant DNA controls for reactions. The two-step protocol verifies performance while detecting microbes, which allegedly helps minimize false negative results from human error or failing conditions.
“AOAC’s validation of our Salmonella/STEC E. coli assay across the various cannabis matrices is further proof of our platform’s robustness and versatility,” says Dr. Sherman Hom, director of regulatory affairs at Medicinal Genomics. “We are excited that our PathoSEEK® platform is moving in concert with the FDA’s new blueprint to improve food safety by modernizing the regulatory framework, while leveraging the use of proven molecular tools to accelerate predictive capabilities, enhance prevention, and enhance our ability to swiftly adapt to pathogen outbreaks that could impact consumer safety.”
As of now, there are only two cannabis testing labs in Connecticut. Last year, regulators in the state approved a request from AltaSci Labs to raise the testing limits for yeast and mold at their lab from 10,000 colony forming units per gram (cfu/g) up to 1 million. The other lab, Northeast Laboratories, has kept their limits at 10,000 cfu/g.
Connecticut state flag
According to CTInsider.com, that request was approved privately and unannounced and patients were notified via email of the change. Ginny Monk at CTInsider says patients enrolled in Connecticut’s medical cannabis program have been outspoken over safety concerns, a lack of transparency and little voice in the decision-making process.
Connecticut has a small medical cannabis market with roughly 54,000 patients in the program and they are in the midst of readying the launch of their adult-use market.
A yeast and mold test showing colony forming units
Following public outcry regarding the change at the recent Social Equity Council meeting, state regulators have proposed a change to microbial testing regulations. The new rule will set the limit at 100,000 cfu/g for yeast and mold and requires testing for specific forms of Aspergillus, a more harmful type of mold.
Kaitlyn Kraddelt, spokeswoman for Connecticut’s Department of Consumer Protection, the agency in charge of testing regulations for the state’s cannabis program, told CTInsider.com that they involved several microbiologists to develop the new rule. “These new standards, which were drafted in consultation with several microbiologists, will prohibit specific types of yeast and mold in cannabis flower that may cause injury when inhaled and allow 10^5 cfu/g of colony forming units that have no demonstrated injurious impact on human health,” says Krasselt.
The rule change is now undergoing a public comment period, after which the Attorney General’s office will get a review period. If approved, it’ll head to the legislature, where a committee has 45 days to act on it.
Increasing cannabis use across the US has come with increased scrutiny of its health effects. Regulators and healthcare providers are not just concerned about the direct effects of inhaling or consuming cannabinoids, however, but also about another health risk: microbial contamination in cannabis products. Like any other crop, cannabis is susceptible to contamination by harmful pathogens at several points throughout the supply chain, from cultivation and harvesting to distribution. Many state regulators have set limits for microbial populations in cannabis products. Consequently, testing labs must adopt efficient screening protocols to help companies remain compliant and keep their customers safe.
Some of the pathogens common to cannabis flower include Aspergillus fungus species such as A. flavus, A. fumigatus, A. niger and A. terreus. Cannabis might also harbor harmful E. coli and Salmonella species, including Shiga toxin-producing E. coli (STEC). Regulations vary by state, but most have set specific thresholds for how many colony forming units (CFUs) of particular species can be present in a sellable product.
The gold standard method for detecting microbes is running cultures.
Growers and testing labs need to develop a streamlined approach to remain viable. Current methods, including running cultures on every sample, can be expensive and time-consuming, but by introducing a PCR-based screening step first, which identifies the presence of microbial DNA – and therefore the potential for contamination – laboratories can reduce the number of cultures they need to run, saving money and time.
The Risk of Aspergillus Contamination
Contamination from Aspergillus species can bring harm to cannabis growers and their customers. The state of Michigan is currently undergoing the largest cannabis recall in its history from Aspergillus contamination.
If contamination grows out of control, the pathogen can damage the cannabis plant itself and lead to financial losses. Aspergillus can also cause serious illness in consumers, especially those that are immunocompromised. If an immunocompromised person inhales Aspergillus, they can develop aspergillosis, a lung condition with a poor prognosis.
A Two-Step Screening Process
The gold standard method for detecting microbes is running cultures. This technique takes weeks to deliver results and can yield inaccurate CFU counts, making it difficult for growers to satisfy regulators and create a safe product in a timely manner. The use of polymerase chain reaction (PCR) can greatly shorten the time to results and increase sensitivity by determining whether the sample has target DNA.
Using PCR can be expensive, particularly to screen for multiple species at the same time, but a qPCR-based Aspergillus detection assay could lead to significant cost savings. Since the average presumptive positive rate for Aspergillus contamination is low (between 5-10%), this assay can be used to negatively screen large volumes of cannabis samples. It serves as an optional tool to further speciate only those samples that screened positive to comply with state regulations.
Conclusion
Overall, screening protocols have become a necessary part of cannabis production, and to reduce costs, testing labs must optimize methods to become as efficient as possible. With tools such as PCR technology and a method that allows for initial mass screening followed by speciation only when necessary, laboratories can release more samples faster with fewer unnecessary analyses and more success for cannabis producers in the marketplace.
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For as long as consistent state and federal guidelines governing cannabis safety remain elusive, the need for industry self-regulation will be paramount. Cannabis companies must work together to share best practices, establish standard operating procedures and adopt stringent safety measures. By promoting transparency and collaboration, stakeholders can build credibility and consumer trust while fostering a safer and more reputable industry.
