Tag Archives: microbiology

By Dr. Sherman Hom

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.

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)

May 11, 2022

AOAC Launches Cannabis Proficiency Testing Program

By Cannabis Industry Journal Staff

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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.

April 17, 2022

Soapbox

The Need for More Stringent Testing in Cannabis

By Milan Patel

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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.

March 29, 2022

Beyond Compliance: Understanding and Combating Contamination

By Jill Ellsworth MS, RDN, Tess Eidem, Ph.D.

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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.

Petri dish containing the fungus Aspergillus flavus

March 9, 2022

Salmonella & Aspergillus: Controlling Risk in Your Supply Chain

By Cameron Prince

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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.

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.

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.

March 1, 2022

Medicinal Genomics Salmonella and STEC E. coli Multiplex Assay Certified by AOAC

By Cannabis Industry Journal Staff

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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.”

January 3, 2022

Connecticut Seeks to Change Microbial Testing Regulations

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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.

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.

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.

December 17, 2021

Detecting Microbial Contamination in Cannabis

By Mike Clark

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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.

October 26, 2021

bioMérieux Gets AOAC Approval for PCR Detection of STEC and Salmonella in Cannabis

By Cannabis Industry Journal Staff

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bioMérieux, a leader in the in vitro diagnostics space and a supporter of the cannabis testing market, announced last month that they have achieved the first ever AOAC International approval for PCR Multiplex Detection of STEC and Salmonella in cannabis flower for their GENE-UP® PRO STEC/Salmonella Assay. The performance tested method approval for their new assay accomodates simultaneous enrichment and detection of STEC (Shiga Toxigenic Escherichia coli) and Salmonella spp. in cannabis samples.

The method is aimed at increasing efficiency in cannabis testing labs by reducing sample preparation time for microbiological testing. With the single enrichment and real-time multiplex PCR detection, bioMérieux says their new assay can provide reliable detection of STEC and Salmonella in 24 hours using just a single test.

PCR technology is one of the most widely utilized testing methods for detecting pathogens in a variety of matrices. bioMérieux claims it is easy to use, scientifically robust and reduces costs, time spent testing and errors.

Maria McIntyre, cannabis strategic operations business manager at bioMérieux, says that AOAC performance tested method approval is setting the bar for cannabis testing laboratories and furthering cannabis science. “AOAC International impacts cannabis science by setting analytical method standards that act as the benchmark for method validation,” says McIntyre. “This simplifies the validations needed by cannabis laboratories and assures the utmost confidence in product safety and human health.”

August 17, 2021

AOAC Approves Two New Microbiological Assays

By Cannabis Industry Journal Staff

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On August 11, PathogenDx announced that they received an AOAC Performance Tested Methods Certificate for their Quant^Xtotal 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 Quant^Xquantifies 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.