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)
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.”
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.
Cross Contamination – noun – “inadvertent transfer of bacteria or other contaminants from one surface, substance, etc., to another especially because of unsanitary handling procedures. – (Mariam Webster, 2021). Cross contamination is not a new concept in the clinical and food lab industries; many facilities have significant design aspects as well as SOPs to deliver the least amount of contaminants into the lab setting. For cannabis labs, however, often the exponential growth leads to a circumstance where the lab simply isn’t large enough for the number of samples processed and number of analytical instruments and personnel needed to process them. Cross contamination for cannabis labs can mean delayed results, heightened occurrences of false positives, and ultimately lost customers – why would you pay for analysis of your clean product in a dirty facility? The following steps can save you the headaches associated with cross contamination:
Wash (and dry) your hands properly
Flash back to early pandemic times when the Tik Tok “Ghen Co Vy” hand washing song was the hotness – we had little to no idea that the disease would be fueled mostly by aerosol transmission, but the premise is the same, good hand hygiene is good to reduce cross contamination. Hands are often the source of bacteria, both resident (here for the long haul; attached to your hands) and transient (easy to remove; just passing through), as they come into contact with surfaces from the bathroom to the pipettor daily (Robinson et al, 2016). Glove use coupled with adequate hand washing are good practices to reduce cross contamination from personnel to a product sample. Additionally, the type of hand drying technique can reduce the microbial load on the bathroom floors and, subsequently tracked into the lab. A 2013 study demonstrated almost double the contamination from air blade technology versus using a paper towel to dry your hands (Margas et al, 2013).
Design Your Lab for Separation
Microbes are migratory. In fact, E. coli can travel at speeds up to 15 body lengths per second. Compared to the fastest Olympians running the 4X100m relay, with an average speed of 35 feet per second or 6 body lengths, this bacterium is a gold medal winner, but we don’t want that in the lab setting (Milo and Phillips, 2021). New lab design keeps this idea of bacterial travel in mind, but for those labs without a new build, steps can be made to prevent contamination:
Try to keep traffic flow moving in one direction. Retracing steps can lead to contamination of a previous work station
Use separate equipment (e.g. cabinets, pipettes) for each process/step
Separate pre- and post-pcr areas
Physical separation – use different rooms, add walls, partitions, etc.
Establish, Train and Adhere to SOPs
Design SOPs that include everything- from hygiene to test procedures and sanitation.
High turnover for personnel in labs causes myriad issues. It doesn’t take long for a lab that is buttoned up with cohesive workflows to become a willy-nilly hodgepodge of poor lab practices. A lack of codified Standard Operating Procedures (SOPs) can lead to a lab rife with contaminants and no clear way to troubleshoot the issue. Labs should design strict SOPs that include everything from hand hygiene to test procedures and sanitation. Written SOPs, according to the WHO, should be available at all work stations in their most recent version in order to reduce biased results from testing (WHO, 2009). These SOPs should be relayed to each new employee and training on updated SOPs should be conducted on an ongoing basis. According to Sutton, 2010, laboratory SOPs can be broken down into the following categories:
Quality requirements
Media
Cultures
Equipment
Training
Sample handling
Lab operations
Testing methodology
Data handling/reporting/archiving
Investigations
Establish Controls and Monitor Results
Scanning electron micrograph shows a colony of Salmonella typhimurium bacteria. Photo courtesy of CDC, Janice Haney Carr
It may be difficult for labs to keep tabs on positivity and fail rates, but these are important aspects of a QC regimen. For microbiological analysis, labs should use an internal positive control to validate that 1) the method is working properly and 2) positives are a result of target analytes found in the target matrix, not an internal lab contamination strain. Positive controls can be an organism of choice, such as Salmonella Tranoroa, and can be tagged with a marker, such as Green Fluorescent Protein in order to differentiate the control strain. These controls will allow a lab tech to discriminate between a naturally contaminated specimen vs. a positive as a result of cross-contamination.
Labs should, in addition to having good QC practices, keep track of fail rates and positivity rates. This can be done as total lab results by analysis, but also can be broken down into customers. For instance, a lab fail rate for pesticides averages 4% for dried flower samples. If, during a given period of review, this rate jumps past 6% or falls below 2%, their may be an issue with instrumentation, personnel or the product itself. Once contamination is ruled out, labs can then present evidence of spikes in fail rates to growers who can then remediate in their own facilities. These efforts in concert will inherently drive down fail rates, increase lab capacity and efficiency, and result in cost savings for all parties associated.
Continuous Improvement is the Key
Cannabis testing labs are, compared to their food and clinical counterparts, relatively new. The lack of consistent state and federal regulation coupled with unfathomable growth each year, means many labs have been in the “build the plane as you fly” mode. As the lab environment matures, simple QC, SOP and hygiene changes can make an incremental differences and drive improvements for labs as well as growers and manufacturers they support. Lab management can, and should, take steps to reduce cross contamination, increase efficiency and lower costs; The first step is always the hardest, but continuous improvement cannot begin until it has been taken.
References
Margas, E, Maguire, E, Berland, C. R, Welander, F, & Holah, J. T. (2013). Assessment of the environmental microbiological cross contamination following hand drying with paper hand towels or an air blade dryer. Journal of Applied Microbiology, 115(2), 572-582.
Milo, M., and Phillips, R. (2021). How fast do cells move? Cell biology by the numbers. Retrieved from http://book.bionumbers.org/how-fast-do-cells-move/
Robinson, Andrew L, Lee, Hyun Jung, Kwon, Junehee, Todd, Ewen, Perez Rodriguez, Fernando, & Ryu, Dojin. (2016). Adequate Hand Washing and Glove Use Are Necessary To Reduce Cross-Contamination from Hands with High Bacterial Loads. Journal of Food Protection, 79(2), 304–308. https://doi.org/10.4315/0362-028X.JFP-15-342
Sutton, Scott. (2010). The importance of a strong SOP system in the QC microbiology lab. Journal of GXP Compliance, 14(2), 44.
World Health Organization. (2009). Good Laboratory Practice Handbook. Retrieved from https://www.who.int/tdr/publications/documents/glp-handbook.pdf
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.
In 1887, Julius Petri invented a couple of glass dishes, designed to grow bacteria in a reproducible, consistent environment. The Petri dish, as it came to be known, birthed the scientific practice of agar cultures, allowing scientists to study bacteria and viruses. The field of microbiology was able to flourish with this handy new tool. The Petri dish, along with advancements in our understanding of microbiology, later developed into the modern field of microbial testing, allowing scientists to understand and measure microbial colonies to detect harmful pathogens in our food and water, like E. coli and Salmonella, for example.
The global food supply chain moves much faster today than it did in the late 19th century. According to Milan Patel, CEO of PathogenDx, this calls for something a little quicker. “Traditional microbial testing is tedious and lengthy,” says Patel. “We need 21st century pathogen detection solutions.”
Milan Patel first joined the parent company of PathogenDx back in 2012, when they were more focused on clinical diagnostics. “The company was predominantly built on grant funding [a $12 million grant from the National Institute of Health] and focused on a niche market that was very specialized and small in terms of market size and opportunity,” says Patel. “I realized that the technology had a much greater opportunity in a larger market.”
Milan Patel, CEO of PathogenDx Photo: Michael Chansley
He thought that other markets could benefit from that technology greatly, so the parent company licensed the technology and that is how PathogenDx was formed. Him and his team wanted to bring the product to market without having to obtain FDA regulatory approval, so they looked to the cannabis market. “What we realized was we were solving a ‘massive’ bottleneck issue where the microbial test was the ‘longest test’ out of all the tests required in that industry, taking 3-6 days,” says Patel. “We ultimately realized that this challenge was endemic in every market – food, agriculture, water, etc. – and that the world was using a 140-year-old solution in the form of petri dish testing for microbial organisms to address challenges of industries and markets demanding faster turnaround of results, better accuracy, and lower cost- and that is the technology PathogenDx has invented and developed.”
While originally a spinoff technology designed for clinical diagnostics, they deployed the technology in cannabis testing labs early on. The purpose was to simplify the process of testing in an easy approach, with an ultra-low cost and higher throughput. Their technology delivers microbial results in less than 6 hours compared to 24-36 hours for next best option.
The PathogenDx Microarray
Out of all the tests performed in a licensed cannabis testing laboratory, microbial tests are the longest, sometimes taking up to a few days. “Other tests in the laboratory can usually be done in 2-4 hours, so growers would never get their microbial testing results on time,” says Patel. “We developed this technology that gets results in 6 hours. The FDA has never seen something like this. It is a very disruptive technology.”
When it comes to microbial contamination, timing is everything. “By the time Petri dish results are in, the supply chain is already in motion and products are moving downstream to distributors and retailers,” Patel says. “With a 6-hour turnaround time, we can identify where exactly in the supply chain contaminant is occurring and spreading.”
The technology is easy to use for a lab technician, which allows for a standard process on one platform that is accurate, consistent and reproduceable. The technology can deliver results with essentially just 12 steps:
Take 1 gram of cannabis flower or non-flower sample. Or take environmental swab
Drop sample in solution. Swab should already be in solution
Vortex
Transfer 1ml of solution into 1.5ml tube
A look at how the sample is added to the microarray
Conduct two 3-minute centrifugation steps to separate leaf material, free-floating DNA and create a small pellet with live cells
Conduct cell lysis by adding digestion buffer to sample on heat blocks for 1 hour
Conduct Loci enhancement PCR of sample for 1 hour
Conduct Labelling PCR which essentially attaches a fluorescent tag on the analyte DNA for 1 hour
Pipette into the Multiplex microarray well where hybridization of sample to probes for 30 minutes
Conduct wash cycle for 15 minutes
Dry and image the slide in imager
The imager will create a TIFF file where software will analyze and deliver results and a report
Their DetectX product can test for a number of pathogens in parallel in the same sample at the same time down to 1 colony forming unit (CFU) per gram. For bacteria, the bacterial kit can detect E. coli, E. coli/Shigella spp., Salmonella enterica, Listeria and Staph aureus, Stec 1 and Stec 2 E.coli. For yeast and mold, the fungal kit can test for Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger and Aspergillus terreus.
Their QuantX is the world’s first and only multiplex quantification microarray product that can quantify the microbial contamination load for key organisms such as total aerobic bacteria, total yeast & mold, bile tolerant gram negative, total coliform and total Enterobacteriaceae over a dynamic range from 100 CFU/mL up to 1,000,000 CFU/mL.
Not all of the PathogenDx technology is designed for just microbial testing of cannabis or food products. Their EnviroX technology is designed to help growers, processors or producers across any industry identify areas of microbial contamination, being used as a tool for quality assurance and hazard analysis. They conducted industry-wide surveys of the pathogens that are creating problems for cultivators and came up with a list of more than 50 bacterial and fungal pathogens that the EnviroX assay can test for to help growers identify contamination hotspots in their facilities.
Using the EnviroX assay, growers can swab surfaces like vents, fans, racks, workbenches and other potential areas of contamination where plants come in contact. This helps growers identify potential areas of contamination and remediate those locations. Patel says the tool could help growers employ more efficient standard operating procedures with sanitation and sterilization, reducing the facility’s incidence of pathogens winding up on crops, as well as reduction in use of pesticides and fungicides on the product.
Deploying this technology in the cannabis industry allowed Milan Patel and the PathogenDx team to bring something new to the world of microbial testing. Their products are now in more than 90 laboratories throughout the country. The success of this technology provides another shining example of how the cannabis market produces innovative and disruptive ideas that have a major impact on the world, far beyond cannabis itself.
Earlier this month, Colorado cannabis producer Herbal Wellness LLC recalled dozens of batches of cannabis due to positive yeast and mold tests. The Colorado Department of Public Health and Environment (CDPHE) issued a health and safety advisory following the news of microbial contamination.
The Colorado Department of Revenue then identified batches of both medical and recreational cannabis produced by Herbal Wellness that were not even tested for microbial contaminants, which is a requirement for licensed producers in the state. Just a few days later, the Denver Department of Public Health & Environment (DDPHE) issued a bulletin announcing their plans to conduct random tests at dozens of dispensaries.
“In the coming weeks, the Denver Department of Public Health & Environment (DDPHE) will be conducting an assessment in approximately 25 retail marijuana stores to evaluate contaminants in products on store shelves,” reads the bulletin. “DDPHE has worked with epidemiological partners at Denver Public Heath to create the assessment methodology. Participating stores will be randomly identified for inclusion in the assessment.”
“Current METRC inventory lists for each store will be used to randomly identify samples of flower, trim/shake, and pre-rolls. Each sample will be tested for pesticides and total yeast and mold by a state- and ISO-certified marijuana testing facility. Results of their respective testing will be shared with each facility and will also be shared broadly within a write-up of results.”
Today in the states where medical and recreational cannabis is legal, cannabis products purchased from licensed facilities are required to have undergone testing by accredited labs. The compliance testing verifies advertised potency levels and checks for microbial contamination, herbicides, pesticides, fungicides and the presence of mold and mildew, among other potential contaminants.
Until recently, little attention has been given to disposable gloves and their possible involvement in the contamination of the products they handle. What factors should you consider when purchasing gloves?
Disposable Gloves Facts
Disposable gloves, like cannabis products, are not made of equal quality. There are several different types of disposable gloves on the market, and huge variations in glove quality and chemical compositions exist between and within each glove type.
Recent scientific studies have revealed how gloves produced in factories with poor manufacturing standards and raw material ingredients can contaminate the products they handle. High-level toxins in disposable gloves were found to affect lab results, toxins in gloves contaminated the food they touched, and pathogen contamination of unused disposable gloves has been proven. Should the cannabis industry take more interest in the disposable gloves they are using? With so much at stake if compliance test results are compromised, we think so!
Glove Procurement: Factors to Consider
What factors should you consider when purchasing gloves?
Industrial grade gloves- There is no such thing as an industrial grade glove certification, although it does give an incorrect impression that gloves are strong and resilient. Industrial grade means they have not been subjected to inspection nor have passed any specific testing requirements.
Food contact gloves are certified under FDA Title 21 CFR Part 177, which states the components of the glove comply with the FDA regulations and the gloves consist of “substances generally recognized as safe for use in food or food packaging.” Few controls exist for glove manufacturing relating to the reliability of raw materials and manufacturing processes, and costs can be reduced with the use of cheap, toxic materials.
Medical grade gloves have to pass a series of technical tests in order to meet the safety requirements specified by the FDA. Gloves are tested for puncture and abrasion resistance, must meet tension and elongation tests and are also tested for chemical substance resistance. Manufacturers of these gloves must receive 510k certification. As this study shows, even medical gloves can contain high levels of toxic ingredients, affecting laboratory test results.
The Acceptable Quality Level (AQL) refers to a quality standard for measuring pinhole defects- the lower the AQL, the less defects the gloves have. There are no AQL requirements for food grade or industrial grade gloves, meaning there are no guidelines for the number of failures per box. Medical grade gloves must have an AQL of 2.5 or less, meaning 2.5 failed gloves per 100 gloves is an acceptable level.
For Californian cannabis companies, are your disposable gloves Prop. 65 compliant? Accelerator chemicals, such as 2-Mercaptobenzothiazole (MBT) found in some nitrile gloves, have recently been added to the Prop. 65 chemicals known to cause cancer.
How Gloves Can Contaminate Products
Physical, chemical and microbiological hazards have been identified in disposable glove supply chains. Gloves of any grade are not tested for cleanliness (microbial and bioburden levels), raw material toxicity and chemical composition, or pathogen contamination.
100% of glove factories supplying the United States are based in Southeast Asia. These factories are generally self-regulated, with FDA compliance required for a rough outline of the ingredients of the gloves rather than the final product. Few controls are required for glove manufacturing relating to the reliability of raw materials, manufacturing processes and factory compliance or conditions. A clear opportunity exists for accidental or intentional contamination within the glove-making process, especially to reduce costs.
In order to safeguard their customers from product contamination, a selection of tests and certifications, some of which are unique within the glove industry, are being implemented by glove supplier Eagle Protect. These tests make sure Eagle’s gloves coming into the United States are made in clean, well run factories, free of any type of contamination and are consistent in material makeup to original food safe specifications. This glove Fingerprint testing program, consists of a number of proprietary risk reduction steps and targeted third-party testing methods, includes gas chromatography combined with mass spectroscopy (GC/MS); surface free energy determination; in vitro cytotoxicity analysis; and microbial viability-linked metagenomic analysis.
With a great deal of faith placed on a glove supplier’s ability to deliver disposable gloves sight unseen, we believe these tests are essential to further reduce risks or pathogen contamination associated with them, keeping your cannabis products safe.
AOAC INTERNATIONAL is an independent, third party, not-for-profit association and voluntary consensus standards developing organization. Founded in 1884, AOAC INTERNATIONAL was originally coined the Association of Official Agricultural Chemists. Later on, they changed their name to the Association of Official Analytical Chemists. Now that their members include microbiologists, food scientists as well as chemists, the organization officially changed its name to just AOAC INTERNATIONAL.
Much of AOAC’s work surrounds promoting food safety, food security and public health. Their work generally encompasses setting scientific standards for testing methodology, evaluating and adopting test methods and evaluating laboratory proficiency of test methods. The organization provides a forum for scientists to develop microbiological and chemical standards.
In December of 2018, they appointed Dr. Palmer Orlandi as deputy executive director and chief science officer. Dr. Orlandi has an extensive background at the U.S. Food and Drug Administration (FDA), serving the regulatory agency for more than 20 years. Most recently, he was the CSO and research director in the Office of Food and Veterinary Medicine at the FDA. He earned the rank of Rear Admiral and Assistant Surgeon General in 2017.
Dr. Palmer Orlandi is the new Deputy Executive Director and Chief Science Officer at AOAC.
Where It All Began With Cannabis
As recently as three years ago, AOAC began getting involved in the cannabis laboratory testing community, with a working group dedicated to developing standard method performance requirements for AOAC Official MethodsSM for cannabis testing. We sat down with Dr. Palmer Orlandi and a number of AOAC’s leaders to get an update on their progress working with cannabis testing as well as food security and food fraud.
According to Scott Coates, senior director of the AOAC Research Institute, they were approached three years ago to set up a working group for cannabis testing. “We created standards that we call the standard method performance requirements (SMPR®), which are detailed descriptions of what analytical methods should be able to do,” says Coates. “Using SMPRs, we issued a series of calls for methods and looked for methods that meet our standards. So far, we’ve completed four SMPRs- cannabinoids in plant material, cannabinoids in plant extracts, cannabinoids in chocolate (edibles), and one for pesticides in cannabis plant material.” AOAC doesn’t develop methods themselves, but they perform a comprehensive review of the methods and if they deem them acceptable, then the methods can be adopted and published in the AOAC compendium of methods, the Official Methods of Analysis of AOAC INTERNATIONAL.
Deborah McKenzie, senior director of Standards and Official Methods at AOAC
Deborah McKenzie, senior director of Standards and Official MethodsSM at AOAC, says the initial working group set the stage for really sinking their teeth into cannabis testing. “It started with methods for testing cannabinoids in plant dried material and plant extract,” says McKenzie. “That’s where our previous work has started to mold into the current effort we are launching.” McKenzie says they are looking forward to getting more involved with methods regarding chemical contaminants in cannabis, cannabinoids in various foods and consumables, as well as microbial organisms in cannabis. “We are pretty focused on testing labs having reliable and validated analytical solutions as our broad goal right now.”
Moving Forward, Expanding Their Programs
Coates says the work they’ve done over the past few years was more of a singular project, developed strictly for creating standards and to review methods. Now they are currently developing their Cannabis Analytical Science Program (CASP), which is expected to be an ongoing program. “We are looking to fully support the cannabis analytical community as best we can, which will potentially include working on reference materials, proficiency testing, education, training and ISO 17025 accreditation, all particularly as it applies to lab testing in the cannabis industry,” says Coates. “So, this CASP work is a much bigger and broader effort to cover more and to provide more support for labs doing the analysis of cannabis and its constituents, as well as hemp.”
According to Dr. Orlandi, they want this program to have a broad reach in the cannabis testing community. “As Scott pointed out, it’s not just strictly developing standards and methods,” says Dr. Orlandi. “It is going to be as all-encompassing as possible and will lead to training programs, a proficiency testing program and other areas.” Arlene Fox, senior director of AOAC’s Laboratory Proficiency Testing Program, says they are actively engaging in proficiency testing. “We are in the process of evaluating what is out there, what is possible and what’s needed as far as expanding proficiency testing for cannabis labs,” says Fox.
Regulatory Challenges & Obstacles
The obvious roadblock to much of AOAC’s work is that cannabis is still considered a controlled substance. “That creates some challenges for the work that we do in certain areas,” says Dr. Orlandi. “That is why this isn’t just a one-year project. We will work with these challenges and our stakeholders to address them.” AOAC had to put some limits on participation- for example, they had to decide that they cannot look for contributions or collaborations with producers and distributors, so long as cannabis is still a Schedule I controlled substance in the US.
Arlene Fox, senior director of AOAC’s Laboratory Proficiency Testing Program
Muddying the waters even further, the recent signing of the Farm Bill puts a clear distinction between most types of cannabis and industrial hemp. David Schmidt, executive director of AOAC realizes they need to be realistic with their stakeholders and in the eye of federal law.
While scientifically speaking, it’s pretty much the same plant just with slightly different chemical constituents, AOAC INTERNATIONAL has to draw a line in the sand somewhere. “As Palmer suggests, because of the Farm Bill being implemented and hemp being defined now as a legal substance from a controlled substance standpoint, industrial hemp has been given this exclusion,” says Schmidt. “So, we are trying to be realistic now, working with our stakeholders that work with hemp, trying to understand the reality of the federal law. We want to make clear that we can meet stakeholder needs and we want to distinguish hemp from cannabis to remain confident in the legality of it.” Schmidt says this is one of a number of topics they plan on addressing in detail at their upcoming 9thannual 2019 Midyear Meeting, held March 11-14 in Gaithersburg, Maryland.
Uniformity in Methodology: The Future of Cannabis Testing
Dr. Orlandi says his experience at the FDA has prepared him well for the work being done at AOAC. “The role that I served at the FDA prior to joining my colleagues here at AOAC was very similar: And that is to bring together stakeholders to accomplish or to solve a common problem.” Some of their stakeholders in the CASP program include BC Testing, Inc., the Association of Food and Drug Officials (AFDO), Bia Diagnostics, Bio-Rad, Industrial Laboratories, Materia Medica Labs, PerkinElmer, R-Biopharm AG, Supra R & D, TEQ Analytical Laboratories, Titan Analytical and Trilogy Analytical, among others.
David Schmidt, executive director of AOAC
“The underlying reason behind this effort is to create some level of harmonization for standards and methods,” says Dr. Orlandi. “They can be used in the near future to stay ahead of the curve for when regulatory agencies become involved. The idea is that these standards for analytical methods will already be established and as uniform as possible.”
When comparing cannabis to other industries in the US, Scott Coates mentions that most standards are signed off by the federal government. “When we started looking at pesticides in cannabis, it became really clear that we have a number of states doing things differently with different limits of quantification,” says Coates. “Each state, generally speaking, is setting their own standards. As Palmer was saying, one thing we are trying to do with this CASP program eventually will be to have some harmonization, instead of 30 different states having 30 different standards and methods.” So, on a much broader level, their goal for the CASP program is to develop a common set of standard methods, including hemp testing and even the Canadian market. “Hopefully this will be an international collaboration for standards for the methodology,” says Coates. They want to create a common set of standards, setting limits of quantification that will be accepted internationally, that will be accurate and repeatable and for the entire cannabis industry, not just state by state.
Food Authenticity & Fraud
One of the other activities that AOAC just launched recently is the food authenticity and fraud program. As the name implies, the goal is to start developing standards and methods and materials to look at economically adulterated foods, says Dr. Orlandi. That includes non-targeted analyses looking at matrices of food products that may be adulterated with an unknown target, as well as targeted analytes, identifying common adulterants in a variety of food products. “One example in the food industry is fraudulent olive oil,” says Dr. Orlandi. “Honey is another commodity that has experienced adulteration.” He says that in most cases these are economically motivated instances of fraud.
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