When people have to make important decisions, we often consult a third party to increase our knowledge and confidence in a product. For instance, when choosing a car, an individual may weigh heavily on safety ratings and other awards from organizations such as Consumer Reports. These awards are often boasted and a heavy focus in car commercials because it tells the consumer that a third party has deemed their car valuable to own. For more than 100 years, the Association of Official Agricultural Chemists (AOAC® International) has operated in this exact manner, and has set the bar and guidelines for testing in the cannabis industry through its special program called the Cannabis Analytical Science Program, also known as CASP.
The CASP program is designed to develop standards and validation guidance to evaluate testing methods, as well as the methods’ ability to detect the target organism or compound on the cannabis matrix. With the addition of new states permitting the legal sale of both medical and adult use cannabis and no federal governing body overseeing testing regulations, the value of AOAC cannot be understated, as these guidelines allow cannabis testing laboratories to have their own third-party reference to look to when choosing a compliant testing method to implement in their laboratory.
AOAC was founded in 1884 by the US government as the standard setting body in the country and, in 1991, became an independent association known as AOAC International, with a goal of building a reputation as an international, consensus-based standard-setting body and a conformity assessment organization in analytical sciences. As an independent third-party resource, AOAC has the Performance Tested Methods’ (PTM) and Official Methods of AnalysisSM (OMA) programs for certification of analytical testing methods in both biology and chemistry.
If analytical methods, including proprietary test kits, are deemed acceptable, AOAC provides approved certification, their seal of approval that the method works as designed. Though multiple factors are considered to determine if AOAC approval is given; accuracy and precision of the method are among the most important. For example, when validating a cannabis method for microbiology, AOAC will contract an independent testing facility to conduct a series of tests with known spiked samples to measure the recovery limit of the target microorganism. This allows the organization to determine if the method is sensitive enough to be named an AOAC-approved method through either the PTM or OMA conformity programs. Another way of ensuring the validity of results is by conducting an inclusivity and exclusivity study on a method. In this type of experiment, target organisms are tested while also spiking with non-target organisms to see if there will be a high rate of false positives.
In cannabis, discussions have grown surrounding testing of four strains of Aspergillus, which are A. terreus, A. flavus, A. fumigatus and A. niger. By spiking cannabis with one of the four Aspergillus strains and on a separate sample with a non-target Aspergillus strain such as A. clavatus, it ensures that only the target strains are being recognized and recorded on the method being tested.
This methodology limits the likelihood of unconfirmed positives occurring, ensuring the validity of the results. Of course, when a method is undergoing an actual AOAC evaluation for approval, the testing requirements for both the sensitivity and inclusivity/exclusivity experiments are much more thorough than the explanation above.
Regardless of which AOAC-approved method you select, you can feel confident that most of the “heavy-lifting” is done and that the method is accurate and precise enough to implement in a cannabis testing facility. In turn, the cannabis testing laboratory then only needs to complete their own internal method verification to ensure the method works with their processes, people, environment and product, but on a much smaller scale and aligns with state regulations.
On a consumer safety level, AOAC-approved methods are designed to keep cannabis consumers safe. Whether they are an adult using cannabis or medicinal cannabis patient, the product that is being sold should be held to the highest safety standards. By having a laboratory that is utilizing an independently approved AOAC method, an additional layer of confidence is achieved that the product being consumed is safe. This ultimately limits the number of costly recalls from dispensaries and minimizes risk to consumers. At the end of the day, cannabis testing laboratories want to keep the public safe and it is our job to do so. This means implementing these independently approved methods from agencies such as AOAC at various touch points in the seed to sale cycle to ensure the data is validated and reliable.
Overall, just as it is equally important to get a non-biased and reputable third-party approach to your automobile search, a scientist that is responsible for choosing methods in their cannabis compliance laboratory should also consider these third-party approvals. As a scientist, the goal every day is to report accurate data to help the client and the consumer equally. The cannabis compliance laboratories are the last line of defense in preventing harmful or contaminated products from getting into the marketplace and any extra assurance we have with our testing methodology is always encouraged. Ultimately, AOAC’s work is important and their standard of quality and safety is a must-have in the cannabis laboratory.
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)
As the demand for legal cannabis continues to rise and more states come online, it is imperative to enact more rigorous and comprehensive testing solutions to protect the health of consumers. People use cannabis products for wellness and to find relief; they should not be susceptible to consuming pathogens and falling ill. Especially for immunocompromised consumers, the consequences of consuming contaminated cannabis or hemp are dire. Of course, there should be federal standards for pathogen testing requirements like we have for the food industry. But right now, as cannabis is not yet federally legal, testing regulations vary between states and in many states, testing requirements are too loose and enforcement is minimal. It is up to state legislators, regulators and cannabis operators to protect the health of consumers through implementing more stringent testing.
From the outset, the environmental elements needed to grow cannabis – heat, light, humidity, soil – make cannabis ripe for pathogens to proliferate. Even when growers follow strict sanitation procedures through the supply chain from seed to sale, contaminations can still occur. Cannabis companies need to be hypervigilant and proactive about testing, not just reactive. The lack of regulations in some states is alarming, and as the cannabis industry is highly competitive and so many companies have emerged in a short time, there are unfortunately unscrupulous actors that have skated by in a loose regulatory landscape, just in the game to make a quick buck, even at the expense of consumer health. And there are notable instances where states do not have enforcement in place to deter harmful manufacturing practices. For instance, there are some states that don’t mandate moisture control and there have been incidents of companies watering down flower so it has more weight and thus can be sold at a higher cost – all the while that added moisture leads to mold, harming the consumer. This vicious circle driven by selfish human behavior needs to be broken by stricter regulations and enforcement.
While in the short term, looser testing regulations may save companies some money, in the long run these regulatory environments carry significant economic repercussions and damage the industry at large, most importantly injury or death to customers and patients. Recalls can tarnish a company’s brand and reputation and cause sales and stock prices to tank, and since cannabis legalization is such a hotly contested issue, the media gloms onto these recalls, which opponents to legalization then leverage to justify their stance. In order to win the hearts and minds of opponents and bring about federal legalization sooner, we need safer products so cannabis won’t be cast in such a dangerous, risky light.
Certainly, there’s a bit of irony at play here – the lack of federal regulations heightens the risk of contaminated cannabis reaching consumers, and on the flip side recalls are used by opponents to justify stigmatizing the plant and keeping it illegal. Nevertheless, someday in the not-too-distant future, cannabis will be legalized at the federal level. And when that day happens, federal agents will aggressively test and regulate cannabis; they’ll swab every area in facilities and demand thorough records of testing up and down the supply chain; current good manufacturing practices (cGMP) will be mandated. No longer will violations result just in a slap on the wrist – businesses will be shut down. To avoid a massive shock to the system, it makes sense for cannabis companies to pivot and adopt rigorous and wide-sweeping testing procedures today. Wait for federal legalization, and you’ll sink.
Frankly, the current landscape of cannabis regulation is scary and the consequences are largely yet to be seen. Just a few months ago, a Michigan state judge reversed part of a recall issued by the state’s Marijuana Regulatory Agency (MRA) on cannabis that exceeded legal limits of yeast, mold and aspergillus, bringing contaminated cannabis back to shelves without even slapping a warning label on the packaging to inform consumers of the potential contamination. This is a classic case of the power of the dollar prevailing over consumer safety and health. Even in well-established markets, the lack of regulations is jarring. For example, before this year in Colorado, testing for aspergillus wasn’t even required. (Aspergillus inhalation, which can cause Aspergillosis, can be deadly, especially for people who are immunocompromised). Many states still allow trace amounts of aspergillus and other pathogens to be present in cannabis samples. While traces may seem inconsequential in the short term, what will happen to frequent consumers who have been pinging their lungs with traces of pathogens for 30 years? Consistently inhaling trace amounts of pathogens can lead to lung issues and pulmonary disease down the road. Look what happened to people with breathing and lung issues during the last two years with COVID. What’s going to happen to these people when the next pandemic hits?
We need state regulators and MSOs to step up and implement more aggressive testing procedures. These regulators and companies can create a sea of change in the industry to better protect the health and well-being of consumers. Just complying with loose regulations isn’t good enough. We need to bring shortcomings around testing into the limelight and demand better and more efficient regulatory frameworks. And we should adopt the same standards for medical and adult use markets. Right now, several states follow cGMP for medical but not adult use – that’s ridiculous. Potentially harming consumers goes against what activists seeking legalization have been fighting for. Cannabis, untainted, provides therapeutic and clinical value not just to medical patients but to all consumers; cannabis companies should promote consumer health through their products, not jeopardize it.
For best practices, companies should conduct tests at every step in the supply chain, not just test end products. And testing solutions should be comprehensive. Most of the common tests used today are based on petri dishes, an archaic and inefficient technology dating back over a century, which require a separate dish to test for each pathogen of interest. If you’re waiting three to five days to see testing results against fifteen pathogens and a pathogen happens to be present, by the time you see results, the pathogen could have spread and destroyed half of your crops. So, not only do petri dishes overburden state-run labs, but due to their inherent inefficiencies, relying on these tests can significantly eat into cannabis companies’ revenues. At PathogenDx, we’ve created multiplexing solutions that can identify and detect up to 50 pathogens in a single test and yield accurate results in six hours. To save cannabis companies money in the long run and to make sure pathogens don’t slip through the cracks, more multiplexing tests like the ones we’ve created should be implemented in state labs.
Right now, while the regulatory landscape is falling short in terms of protecting consumer health, better solutions already exist. I urge state regulators and cannabis companies to take testing very seriously, be proactive and invest in creating better testing infrastructure today. Together, we can protect the health of consumers and create a stronger, more trustworthy and prosperous cannabis industry.
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.
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.
On August 11, PathogenDx announced that they received an AOAC Performance Tested Methods Certificate for their QuantX total yeast and mold test. Six days later, on August 17, Medicinal Genomics announced that AOAC approved their PathoSEEK 5-Color Aspergillus Multiplex Assays under the same AOAC Performance Tested Methods program.
Both assays are specifically designed with cannabis and hemp testing in mind and designed to expedite and simplify microbiological testing. PathogenDx’s QuantX quantifies the total amount of yeast and mold in a sample while also measuring against safety standards.
In addition to the total yeast and mold count test, PathogenDx has also introduced a 96-well plate, improved sample preparation and new data reporting with a custom reporting portal for compliance testing.
The Medicinal Genomics platform can detect four species, including A. flavus, A. fumigatus, A. niger, and A. terreus in both flower and infused edibles. The PathoSEEK microbial testing platform uses a PCR-based assay and provides an internal plant DNA control for every reaction.
This technique verifies the performance of the assay when detecting pathogens, allegedly minimizing false negative results commonly due to set up errors and experimental conditions.
AOAC International is a standards organization that works in the cannabis testing space through their CASP program to evaluate and approve standard testing methods for the industry.
In this “Leaders in Cannabis Testing” series of articles, Green interviews cannabis testing laboratories and technology providers that are bringing unique perspectives to the industry. Particular attention is focused on how these businesses integrate innovative practices and technologies to navigate a rapidly changing landscape of regulatory constraints and B2B demand.
PathogenDx is an Arizona-based provider of microbial testing technologies. Since their inception in 2014, they have broadened their reach to 26 states in the US. In addition to cannabis product testing, PathogenDx also provides technologies for food safety testing, environmental testing and recently started offering human diagnostics testing to support COVID-19 response efforts.
We interviewed Milan Patel, CEO and co-founder of PathogenDx. Milan founded PathogenDx as a spin-off from one of his investments in a clinical diagnostics company testing for genetic markers in transplant organs. Prior to PathogenDx, Milan worked in finance and marketing at Intel and later served as CFO at Acentia (now Maximus Federal).
Aaron Green: What’s the history of PathogenDx?
Milan Patel: PathogenDx was effectively a spin-off of a clinical diagnostics company that my partner Dr. Mike Hogan, the inventor of the technology, had founded when he was a professor at the University of Arizona, but previously at Baylor Medical College back in 2002. I had invested in the company back then and I had realized that his technology had a broad and wide sweeping impact for testing – not just for pathogens in cannabis specifically, but also for pathogens in food, agriculture, water and even human diagnostics. In the last 14 months, this became very personal for every single person on the planet having been impacted by SARS-CoV-2, the viral pathogen causing Covid-19. The genesis of the company was just this, that human health, food and agricultural supply, and the environment has and will continue to be targeted by bacterial, fungal and viral pathogens impacting the safety and health of each human on the planet.
We founded PathogenDx and we pivoted the company from its original human organ transplant genetics market scope into the bigger markets; we felt the original focus was too niche for a technology with this much potential. We licensed the technology, and we repurposed it into primarily cannabis. We felt that achieving commercial success and use in the hands of cannabis testing labs at the state level where cannabis was first regulated was the most logical next step. Ultimately, our goal was and is to move into markets that are approved at the federal regulatory side of the spectrum, and that is where we are now.
Green: What year was that?
Milan Patel, CEO and Co-Founder of PathogenDx Photo credit: Michael Chansley
Patel: 2014.
Green: So, PathogenDx started in cannabis testing?
Patel: Yes, we started in cannabis testing. We now have over 100 labs that are using the technology. There is a specific need in cannabis when you’re looking at contamination or infection.
In the case of contamination on cannabis, you must look for bacterial and fungal organisms that make it unsafe, such as E. coli, or Salmonella or Aspergillus pathogens. We’re familiar with recent issues like the romaine lettuce foodborne illness outbreaks at Chipotle. In the case of fungal organisms such as Aspergillus, if you smoke or consume contaminated cannabis, it could have a huge impact on your health. Cannabis regulators realized that to ensure public health and safety there was more than just one pathogen – there were half a dozen of these bugs, at a minimum, that could be harmful to you.
The beauty of our technology, using a Microarray is that we can do what is called a multiplex test, which means you’re able to test for all bacterial and fungal pathogens in a single test, as opposed to the old “Adam Smith” model, which tests each pathogen on a one-by-one basis. The traditional approach is costly, time consuming and cumbersome. Cannabis is such a high value crop and producers need to get the answer quickly. Our tests can give a result in six hours on the same day, as opposed to the two or three days that it takes for these other approved methods on the market.
Green: What is your business model? Is there equipment in addition to consumables?
Patel: Our business model is the classic razor blade model. What that means is we sell equipment as well as the consumables – the testing kits themselves.
The PathogenDx technology uses standard, off-the-shelf lab equipment that you can find anywhere. We didn’t want to make the equipment proprietary so that a lab has to buy a specific OEM branded product. They can use almost any equipment that’s available commercially. We wanted to make sure that labs are only paying a fraction of the cost to get our equipment, as opposed to using other vendors. Secondly, the platform is open-ended, meaning it’s highly flexible to work with the volumes that different cannabis labs see daily, from high to low.
One equipment set can process many different types of testing kits. There are kits for regulated testing required by states, as well as required environmental contamination.
Green: Do you provide any in-house or reference lab testing?
Patel: We do. We have a CLIA lab for clinical testing. We did this about a year ago when we started doing COVID testing.
We don’t do any kind of in-house reference testing for cannabis, though we do use specific reference materials or standards from Emerald Scientific, for example, or from NCI. Our platform is all externally third-party reference lab tested whether it’s validated by our external cannabis lab customers or an independent lab. We want our customers to make sure that the actual test works in their own hands, in their own facility by their own people, as opposed to just shrugging our shoulders and saying, “hey, we’ve done it ourselves, believe us.” That’s the difference.
Green: Can you explain the difference between qPCR and endpoint PCR?
Patel: The difference between PathogenDx’s Microarray is it uses endpoint PCR versus qPCR (quantitative real time PCR). Effectively, our test doesn’t need to be enriched. Endpoint PCR delivers a higher level of accuracy, because when it goes to amplify that target DNA, whether it’s E. coli, Salmonella or Aspergillus pieces, it uses all the primer reagent to its endpoint. So, it amplifies every single piece of an E. Coli (for example) in that sample until the primer is fully consumed. In the case of qPCR, it basically reaches a threshold and then the reaction stops. That’s the difference which results in a much greater level of accuracy. This provides almost 10 times greater sensitivity to identify the pathogen in that sample.
The second thing is that we have separated out how the amplified sample hybridizes to the probe. In the case of our assay, we have a microarray with a well in it and we printed the actual probe that has the sequence of E. coli in there, now driving 100% specificity. Whereas in the qPCR, the reaction is not only amplifying, but it’s also basically working with the probe. So, in that way, we have a higher level of efficiency in terms of specificity. You get a definite answer exactly in terms of the organism you’re looking for.
In terms of an analogy, let’s take a zip code for example which has the extra four digits at the end of it. In the case of endpoint PCR, we have nine digits. We have our primer probes which represent the standard five digits of a zip code, and the physical location of the probe itself in the well which serves as the extra four digits of that zip code. The analyte must match both primary and secondary parts of the nine-digit zip code for it to lock in, like a key and a lock. And that’s the way our technology works in a nutshell.
Endpoint PCR is completely different. It drives higher levels of accuracy and specificity while reducing the turnaround time compared to qPCR – down to six hours from sample to result. In qPCR, you must enrich the sample for 24 to 48 hours, depending on bacteria or fungus, and then amplification and PCR analysis can be done in one to three hours. The accuracies and the turnaround times are the major differences between the endpoint PCR and qPCR.
Green: If I understand correctly, it’s a printed microarray in the well plate?
Patel: That’s correct. It’s a 96-well plate, and in each well, you’ve now printed all the probes for all targets in a single well. So, you’re not running more than one well per target, or per organism like you are for qPCR. You’re running just one well for all organisms. With our well plates, you’re consuming fewer wells and our patented foil-cover, you only use the wells you need. The unused wells in the well plate can be used in future tests, saving on costs and labor.
Green: Do you have any other differentiating IP?
The PathogenDx Microarray
Patel: The multiplex is the core IP. The way we process the raw sample, whether it’s flower or non-flower, without the need for enrichment is another part of the core IP. We do triplicate probes in each well for E. Coli, triplicate probes for Salmonella, etc., so there are three probes per targeted organism in each of the wells. We’re triple checking that you’re definitively identifying that bug at the end of the day. This is the cornerstone of our technology.
We were just approved by the State of New York, and the New York Department of Health has 13 different organisms for testing on cannabis. Think about it: one of the most rigorous testing requirements at a state level – maybe even at a federal level – and we just got approved for that. If you had to do 13 organisms separately, whether it’s plate culture or qPCR, it would become super expensive and very difficult. It would break the very backs of every testing lab to do that. That’s where the multiplexing becomes tremendously valuable because what you’re doing is leveraging the ability to do everything as a single test and single reaction.
Green: You mentioned New York. What other geographies are you active in?
Patel: We’re active in 26 different states including the major cannabis players: Florida, Nevada, California, Arizona, Michigan, New York, Oklahoma, Colorado and Washington – and we’re also in Canada. We’re currently working to enter other markets, but it all comes down to navigating the regulatory process and getting approval.
We’re not active currently in other international markets yet. We’re currently going through the AOAC approval process for our technology and I’m happy to say that we’re close to getting that in the next couple of months. Beyond that, I think we’ll scale more internationally.
I am delighted to say that we also got FDA EUA federal level authorization of our technology which drives significant credibility and confidence for the use of the technology. About a year ago, we made a conscious choice to make this technology federally acceptable by going into the COVID testing market. We got the FDA EUA back on April 20, ironically. That vote of confidence by the FDA means that our technology is capable of human testing. That has helped to create some runway in terms of getting federalized with both the FDA and the USDA, and certification by AOAC for our different tests.
Green: Was that COVID-19 EUA for clinical diagnostics or surveillance?
Patel: It was for clinical diagnostics, so it’s an actual human diagnostic test.
Green: Last couple of questions here. Once you find something as a cannabis operator, whether its bacteria or fungus, what can you do?
Patel: There are many services that are tied into our ecosystem. For example, we work with Willow Industries, who does remediation.
There’s been a lot of criticism around DNA based technology. It doesn’t matter if it’s qPCR or endpoint PCR. They say, “well, you’re also including dead organisms, dead DNA.” We do have a component of separating live versus dead DNA with a biomechanical process, using an enzyme that we’ve created, and it’s available commercially. Labs can test for whether a pathogen is living or dead and, in many cases, when they find it, they can partner with remediation companies to help address the issue at the grower level.
Another product we offer is an EnviroX test, which is an environmental test of air and surfaces. These have 50 pathogens in a single well. Think about this: these are all the bad actors that typically grow where soil is – the human pathogens, plant pathogens, powdery mildew, Botrytis, Fusarium – these are very problematic for the thousands of growers out there. The idea is to help them with screening technology before samples are pulled off the canopy and go to a regulated lab. We can help the growers isolate where that contamination is in that facility, then the remediation companies can come in, and help them save their crop and avoid economic losses.
Green: What are you most interested in learning about?
Patel: I would prefer that the cannabis industry not go through the same mistakes other industries have gone through. Cannabis started as a cottage industry. It’s obviously doubled every year, and as it gets scaled, the big corporations come in. Sophistication, standards, maturity all help in legitimacy of a business and image of an industry. At the end of the day, we have an opportunity to learn from other industries to really leapfrog and not have to go through the same mistakes. That’s one of the things that’s important to me. I’m very passionate about it.
One thing that I’ll leave you with is this: we’re dealing with more bugs in cannabis than the food industry. The food industry is only dealing with two to four bugs and look at the number of recalls they are navigating – and this is a multi-billion-dollar industry. Cannabis is still a fraction of that and we’re dealing with more bugs. We want to look ahead and avoid these recalls. How do you avoid some of the challenges around antimicrobial resistance and antibiotic resistance? We don’t want to be going down that road if we can avoid it and that’s sort of a personal mission for myself and the company.
Cannabis itself is so powerful, both medicinally as well as recreationally, and it can be beneficial for both consumers and industry image if we do the right things, and avoid future disasters, like the vaping crisis we went through 18 months ago because of bad GMPs. We must learn from those industries. We’re trying to make it better for the right reasons and that’s what’s important to me.
Green: Okay, great. That concludes the interview. Thank you, Milan.
Patel: Thank you for allowing me to share my thoughts and your time, Aaron.
Testing cannabis and cannabis derived products for microbiological contamination should be a straightforward conversation for testing labs and producers. However, a patchwork of regulations and a wide variety of perspectives on what we should, or should not, be looking for has left much of the cannabis industry searching for reliable answers.
Organizations like the AOAC are taking the first crack at creating standardization in the field but there is still a long way to go. In this conversation, we would like to discuss the general requirements that almost all states share and where we see the industry headed as jurisdictions start to conform to the recommendations of national organizations like AOAC.
We sat down with Anna Klavins and Jessa Youngblood, two cannabis testing experts at Hardy Diagnostics, to get their thoughts on microbiology testing in the current state of the cannabis industry.
Q: What are the biggest challenges facing cannabis testing labs when it comes to microbiology?
The CompactDry Yeast and Mold Rapid plate provides fast results.
Anna Klavins & Jessa Youngblood:For microbiology testing, it comes down to a lack of standardization and approved methods for cannabis. In the US, cannabis regulation is written on a state-by-state level. As a result, the rules that govern every aspect of bringing these materials to market is as unique and varied as the jurisdiction writing them. When we are speaking specifically about microbiology, the question always comes back to yeast and mold testing. For some, the challenge will often be centered on the four main Aspergillus species of concern – A. terreus, A. niger, A. fumigatus, and A. flavus. For others, it will be the challenges of total count testing with yeast, mold, and bacteria. These issues become even more troublesome by the lack of recognized standard methodology. Typically, we expect the FDA, USP, or some other agency to provide the guidelines for industry – the rules that define what is safe for consumption. Without federal guidance, however, we are often in a situation where labs are required to figure out how to perform these tests on their own. This becomes a very real hurdle for many programs.
Q: Why is it important to use two different technologies to achieve confirmation?
Dichloran Rose Bengal Chloramphenicol (DRBC) Agar is recommended for the enumeration of yeasts and molds.
Klavins & Youngblood: The push for this approach was borne out of the discussions happening within the industry. Scientists and specialists from across disciplines started getting together and creating groups to start to hash out problems which had arisen due to a lack of standardization. In regards to cannabis testing, implementing a single method for obtaining microbiology results could be unreliable. When clients compared results across labs, the inconsistencies became even more problematic and began to erode trust in the industry. As groups discussed the best way to prove the efficacy of their testing protocol, it quickly became apparent that relying on a single testing method was going to be inadequate. When labs use two different technologies for microbiology testing, they are able to eliminate the likelihood of false positives or false negatives, whichever the case may be. In essence, the cannabis testing laboratories would be best off looking into algorithms of detecting organisms of interest. This is the type of laboratory testing modeled in other industries and these models are starting make their way into the cannabis testing space. This approach is common in many food and pharma applications and makes sense for the fledgling cannabis market as well.
About Anna Klavins
Anna Klavins earned a Molecular and Cellular Biology B.S. degree from Cal Poly San Luis Obispo while playing for the Cal Poly Division I NCAA women’s tennis team. Since joining Hardy Diagnostics in mid-2016, she has gained experience in FDA submissions [510(k)] for class II microbiology in vitro devices. She has worked on 15 projects which led to a microbiology device becoming FDA cleared. She has recently begun participating in the AOAC Performance Tested Methods program.
About Jessa Youngblood
Jessa Youngblood is the Food, Beverage and Cannabis Market Coordinator for Hardy Diagnostics. A specialist in the field of cannabis microbiology for regulatory compliance, she is seated with the AOAC CASP committee working on standard methods for microbiological testing in cannabis and hemp. She also sits on the NCIA Scientific Advisory Council as well as the ASTM Cannabis Council.
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AOAC was founded in 1884 by the US government as the standard setting body in the country and, in 1991, became an independent association known as AOAC International, with a goal of building a reputation as an international, consensus-based standard-setting body and a conformity assessment organization in analytical sciences. As an independent third-party resource, AOAC has the Performance Tested Methods’ (PTM) and Official Methods of AnalysisSM (OMA) programs for certification of analytical testing methods in both biology and chemistry.
In cannabis, discussions have grown surrounding testing of four strains of Aspergillus, which are A. terreus, A. flavus, A. fumigatus and A. niger. By spiking cannabis with one of the four Aspergillus strains and on a separate sample with a non-target Aspergillus strain such as A. clavatus, it ensures that only the target strains are being recognized and recorded on the method being tested.
On a consumer safety level, AOAC-approved methods are designed to keep cannabis consumers safe. Whether they are an adult using cannabis or medicinal cannabis patient, the product that is being sold should be held to the highest safety standards. By having a laboratory that is utilizing an independently approved AOAC method, an additional layer of confidence is achieved that the product being consumed is safe. This ultimately limits the number of costly recalls from dispensaries and minimizes risk to consumers. At the end of the day, cannabis testing laboratories want to keep the public safe and it is our job to do so. This means implementing these independently approved methods from agencies such as AOAC at various touch points in the seed to sale cycle to ensure the data is validated and reliable.
