Tag Archives: microbiology

dry cannabis plants

Moisture Matters: Why Humidity Can Make or Break a Cannabis Cultivator’s Bottom Line

By Sean Knutsen
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dry cannabis plants

Vintners have known for centuries that every step in the winemaking process—from cultivation and harvest techniques to fermentation, aging and bottling—has immense impact on the quality and value of the final product.

And that same level of scrutiny is now being applied to cannabis production.

As someone who has worked in the consumer-packaged goods (CPG) space for decades, I’ve been interested in finding out how post-harvest storage and packaging affect the quality and value of cannabis flower. After digging into the issue some more, storage conditions and humidity levels have indeed come into focus as major factors, beyond just the challenges of preventing mold.

Weighty Matters

I enlisted my research team at Boveda, which has studied moisture control in all manner of manufactured and natural CPG products, to look closer at what’s happening with cannabis once it leaves the cultivation room. There’s not a lot of research on cannabis storage—we checked—and so we explored this aspect further. We were frankly surprised by what a big effect evaporation has on quality and how this is playing out on the retail level.

We suspected moisture loss could affect the bottom line too, and so we did some number-crunching.

It’s well understood that the weight of cannabis flower directly correlates with its profitability—the heavier the yield, the higher the market value. Here’s what our analysis found: A mere 5% dip below the optimal relative humidity (RH) storage environment eliminates six pounds per every 1,000 pounds of cannabis flower. At $5 per gram wholesale, that works out to upwards of $13,500 in lost revenue—and that’s with just a 5% drop in RH below the target range of 55-65% established by ASTM International, an independent industry standards organization.

We also purchased flower at retailers in multiple state markets and commissioned a lab to test the samples, which revealed that most strains sold today are well below the optimal RH range (55-65%). Regardless of fluctuating wholesale prices, when you do the math it’s clear that tens of thousands of dollars in revenue are simply evaporating into thin air.

Why So Dry?

Historically, cultivators, processors and packagers have emphasized keeping flower below a particular humidity “ceiling” for a reason: Flower that’s too moist is prone to hazardous mold and microbial growth, so it’s understandable that many operators err on the side of being overly dry.

The misconception that cannabis flower can be “rehydrated” is another cause of dryness damage. But this method irrevocably damages the quality of the flower through trichome damage.

trichome close up
The fine outgrowths, referred to as trichomes, house the majority of the plant’s resin

Those delicate plant structures that house the all-important cannabinoids and terpenes become brittle and fragile when stored in an overly dry environment, and are prone to breaking off from the flower; they cannot not be recovered even if the flower is later rehydrated.

When trichomes are compromised, terpenes responsible for the aroma, taste and scent of cannabis also can evaporate. Overly dried-out cannabis doesn’t just lose weight and efficacy—it loses shelf appeal, which is particularly risky in today’s market.

Today’s consumers have an appreciation for how premium flower should look, smell and taste. Rehydration cannot put terpenes back in the flower, nor can it re-attach trichomes to the flower, which is why preservation of these elements is so key.

Cannabis Humidity Control

Cured cannabis flower can remain in storage potentially for months prior to sale or consumption. By the time it reaches the end consumer, much of the cannabis sold in regulated environments in the U.S. and Canada has suffered from dry damage.

dry cannabis plants
Rows of cannabis plants drying and curing following harvest

There are various humidity controls available for cannabis cultivators: desiccants that absorb water vapor; mechanical equipment that alters RH on a larger scale; or two-way humidity-control packets designed for storage containers.

In the CPG sector, with other moisture-sensitive products such as foods and electronics, we’ve seen that employing humidity controls will preserve quality, and cannabis flower is no different.

Saltwater-based humidity control solutions with two-way vapor-phase osmosis technology automatically add or remove water vapor as needed to maintain a constant, predetermined RH level and ensures a consistent level of moisture weight inside the cannabis flower.

Here’s one more notable finding we discovered in our storage research: Third-party lab tests commissioned by Boveda showed cannabis stored with humidity control had terpene and cannabinoid levels that were 15% higher than cannabis stored without.

Cannabis stored within the optimal humidity range maximizes all the qualities that attract and retain customers. Similar to wine-making, when cannabis cultivators focus on quality control they need to look beyond the harvest.

Rapid Pathogen Detection for the 21st Century: A Look at PathogenDx

By Aaron G. Biros
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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:

  1. Take 1 gram of cannabis flower or non-flower sample. Or take environmental swab
  2. Drop sample in solution. Swab should already be in solution
  3. Vortex
  4. Transfer 1ml of solution into 1.5ml tube

    A look at how the sample is added to the microarray
  5. Conduct two 3-minute centrifugation steps to separate leaf material, free-floating DNA and create a small pellet with live cells
  6. Conduct cell lysis by adding digestion buffer to sample on heat blocks for 1 hour
  7. Conduct Loci enhancement PCR of sample for 1 hour
  8. Conduct Labelling PCR which essentially attaches a fluorescent tag on the analyte DNA for 1 hour
  9. Pipette into the Multiplex microarray well where hybridization of sample to probes for 30 minutes
  10. Conduct wash cycle for 15 minutes
  11. Dry and image the slide in imager
  12. 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.

Food processing and sanitation

Key Points To Incorporate Into a Sanitation Training Program

By Ellice Ogle
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Food processing and sanitation

To reinforce the ideas in the article, Sanitation Starting Points: More Than Sweeping the Floors and Wiping Down the Table, the main goal of sanitation is to produce safe food and to keep consumers healthy and safe from foodborne illness. With the cannabis industry growing rapidly, cannabis reaches a larger, wider audience. This population includes consumers most vulnerable to foodborne illness such as people with immunocompromised systems, the elderly, the pregnant, or the young. These consumers, and all consumers, need and deserve safe cannabis products every experience.

GMPSanitation is not an innate characteristic; rather, sanitation is a trained skill. To carry out proper sanitation, training on proper sanitation practices needs to be provided. Every cannabis food manufacturing facility should require and value a written sanitation program. However, a written program naturally needs to be carried out by people. Hiring experienced experts may be one solution and developing non-specialists into an effective team is an alternative solution. Note that it takes every member of the team, even those without “sanitation” in their title, to carry out an effective sanitation program.

Sanitation is a part of the Food and Drug Administration’s Code of Federal Regulations on current Good Manufacturing Practices (GMPs) in manufacturing, packing or holding human food (21 CFR 110). Sanitation starts at the beginning of a food manufacturing process; even before we are ready to work, there are microorganisms, or microbes, present on the work surfaces. What are microbes? At a very basic level, the effects of microbes can be categorized into the good, the bad, and the ugly. The beneficial effects are when microbes are used to produce cheese, beer or yogurt. On the other hand, microbes can have undesirable effects that spoil food, altering the quality aspects such as taste or visual appeal. The last category are microbes that have consequences such as illness, organ failure and even death.In a food manufacturing facility, minimizing microbes at the beginning of the process increases the chance of producing safe food.FDAlogo

Proper sanitation training allows cannabis food manufacturing facilities to maintain a clean environment to prevent foodborne illness from affecting human health. Sanitation training can be as basic or as complex as the company and its processes; as such, sanitation training must evolve alongside the company’s growth. Here are five key talking points to cover in a basic sanitation training program for any facility.

  1. Provide the “why” of sanitation. While Simon Sinek’s TEDx talk “Start with why” is geared more towards leadership, the essential message that “Whether individuals or organizations, we follow those who lead not because we have to, but because we want to.” Merely paying someone to complete a task will not always yield the same results as inspiring someone to care about their work. Providing examples of the importance of sanitation in keeping people healthy and safe will impart a deeper motivation for all to practice proper sanitation. An entertaining illustration for the “why” is to share that scientists at the University of Arizona found that cellphones can carry ten times more bacteria than toilet seats!
  2. Define cleaning and sanitizing. Cleaning does not equal sanitizing. Cleaning merely removes visible soil from a surface while sanitizing reduces the number of microorganisms on the clean surface to safe levels. For an effective sanitation system, first clean then sanitize all utensils and food-contact surfaces of equipment before use (FDA Food Code 2017 4-7).
  3. Explain from the ground up. Instead of jumping into the training of cleaning a specific piece of equipment, start training with the foundational aspects of food safety. For example, a basic instruction on microbiology and microorganisms will lay down the foundation for all future training. Understanding that FATTOM (the acronym for food, acidity, temperature, time, oxygen and moisture) are the variables that any microorganism needs to grow supplies people with the tools to understand how to prevent microorganisms from growing. Furthermore, explaining the basics such as the common foodborne illnesses can reinforce the “why” of sanitation.

    Food processing and sanitation
    PPE for all employees at every stage of processing is essential
  4. Inform about the principles of chemistry and chemicals. A basic introduction to chemicals and the pH scale can go a long way in having the knowledge to prevent mixing incompatible chemicals, prevent damaging surfaces, or prevent hurting people. Additionally, proper concentration (i.e. dilution) is key in the effectiveness of the cleaning chemicals.
  5. Ensure the training is relevant and applicable to your company. Direct proper sanitation practices with a strong master sanitation schedule and ensure accountability with daily, weekly, monthly and annual logs. Develop sanitation standard operating procedures (SSOPs), maintain safety data sheets (SDS’s) and dispense proper protective equipment (PPE).

Overall, sanitation is everyone’s job. All employees at all levels will benefit from learning about proper sanitation practices. As such, it is beneficial to incorporate sanitation practices into cannabis food manufacturing processes from the beginning. Protect your brand from product rework or recalls and, most importantly, protect your consumers from foodborne illness, by practicing proper sanitation.

Product Release: PathogenDx Announces New Products, Branding

By Aaron G. Biros
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According to a press release published earlier this week, PathogenDx, Inc., is expanding their product portfolio and doing some rebranding. The DNA-based pathogen detection testing provider, headquartered in Scottsdale, Arizona, produces microarray testing platforms for the cannabis, agriculture and food and beverage industries. Their rapid testing technology can reportedly identify and detect 50+ pathogens all in a single test, including common pathogens such as E. Coli, Salmonella and Aspergillus.

Here is a look at their new product suite, taken from the press release:

  • DetectX – Tests for the presence of pathogenic microbial organisms down to a single organism, at less than 0.1 CFU/gram for state regulated compliance. Test 96 or more samples a day for multiple state mandated microbial pathogens, with product safety certainty delivered in 6 hours, far more rapid than current industry standards of 72 hours or more.

  • QuantX – The world’s first quantification microarray test for Cannabis. This test measures the microbial load in a sample, while also providing discrimination of the organism content relative to testing standards. Regulatory agencies will now have the opportunity to improve microbial testing standards to ensure safety.

  • EnviroX – With a single swab, one can identify 50+ species and classes of microbes, with quick-turn results, by simply swabbing a grower/cultivation facility surfaces and vents. Submit, identify, and remediate. It’s that simple to mitigate risk to high-value crops.

  • PhytoX – Coming in Summer of 2019, PathogenDx will introduce the ultra-rapid, easy plant pathogen test to detect powdery mildew, gray mold, mites and other microbial bugs that can become destructive threats to one’s crop. Acquire results in 6 hours to intercept and redress infestation that can destroy one’s yield.

According to CEO and Co-Founder Milan Patel, they want their technology to set the standard for product safety testing. “We’re making the accurate testing of cannabis, food and agriculture faster, more definitive and less expensive with trackable results benefitting growers, producers, regulators and consumers worldwide,” says Patel. “Our new brand is inspired by our unique microplex array and is bright, fresh, memorable and expansive, enabling us to move from cannabis only to much larger global consumable markets where we can continue to offer new products and applications for the technology.”

This announcement comes as the company is positioning itself to expand far beyond just the cannabis testing arena, diving into the food and beverage and agriculture industries with a much stronger presence. As recently as late February, the company announced purchases of new real estate, expanding their production capacity, as well as announcing a few key hires, expanding their leadership team. 

Amy-Ankrum-headshot
Soapbox

Quality Assurance for the Cannabis Industry

By Amy Ankrum
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Amy-Ankrum-headshot

Have you paused to consider that quality assurance is a moving target rather than a destination? It is culture within a company that requires constant improvement and change, rather than the work of a select few to reach one defined end goal. Quality, therefore, is not a box that must simply be checked but an overarching and driving force propelling organizations forward.

For those within the cannabis industry and specifically cannabis testing labs, quality assurance is critical to having a successful and thriving business within the rapidly evolving industry. Dr. Kim Ross, who earned her Ph.D. at the University of Colorado in Molecular Biology, and also has worked with multiple cannabis labs, says, “It is not that often that you get a new testing industry born these days and people are scrambling to borrow processes from other industries and apply these to the cannabis industry.” Those within cannabis testing labs are looking towards established industries like water and food testing labs to serve as a quality assurance beacon. Ross elaborates:

The cannabis industry is operating in the absence of federal oversight. If you think about it, the water, food, and pharmaceutical industries have federal oversight. In lieu of that, it is up to states to adopt regulatory practices and enforcement strategies to uphold a level of compliance and data defensibility that these types of regulators have seen in their careers working in the FDA, EPS, NELAC or ISO.

For cannabis testing labs, the stakes are high. First, there is the need to keep up with the rapidly evolving industry climate as more and more states and governing bodies are setting requirements and expectations for quality and compliance. It is in nobody’s best interest to fall behind or be a late adopter to the increasingly regulatory compliance environment.  

Additionally, untrustworthy data sets can have detrimental impacts on people and patients. Medical applications of cannabis require specific results in order to ensure the safety of patients, many of which are immunocompromised. Beyond damage to people and patients, businesses themselves can be hurt if a cannabis testing lab were to present inaccurate or flawed data sets. Ross shared hypothetical examples of potential negative impacts:

 If, for example, you fail a product for microbiology based on false-positive results then it incurs damages to the client because now their product can’t go to market. Additionally, falsely inflated THC results are also a huge problem in the industry, and can result in downstream problems with edible dosing or consumer satisfaction. 

A quality assurance system can minimize risk and maximize adherences to proper procedure, resulting in reliable data. Recalls, product issues and lawsuits cost organizations tremendous amounts of time and money, both to manage the problem at hand and prevent future incidents. Not to mention, the immeasurable damage done to the brand & industry by being viewed as untrustworthy–especially as a consumable product. “Ensuring data defensibility and data integrity protects the laboratory from lawsuits,” says Ross. “That is a really important piece of a quality assurance system for a laboratory.”

One common misconception is viewing quality assurance as a cost center rather than a profitability maximizer. A robust quality assurance system is a competitive advantage–especially for those who are not yet mandated to be compliant to a particular standard, like ISO/IEC 17025, but choose to pursue that accreditation knowing it reflects reliability. In many ways, quality assurance can be summarized as “say what you do, and do what you say”, with a willingness to allow third-party confirmation of your commitment and practice. “Accreditation gives an unbiased stamp of approval that helps ensure data defensibility in the laboratory,” affirms Ross.

Accreditation as a result of quality assurance ultimately leads to reliable and trustworthy data sets. Ross shared:

It might appear to be easy to buy expensive instrumentation, accept samples, and produce data. There are so many ways to do that, some of which are incorrect, and therefore accreditation is really an opportunity to have professionals evaluate methodology and post-analytical data processing to ensure that it is scientifically sound. It is an opportunity for a laboratory to be confident that their processes and reporting procedures are robust and error free.  

Remember: this is a new industry. There aren’t firmly established methods and procedures like other legacy industries. “We are operating in a time and space where there is no standard methodology and that makes oversight by a third party even more important,” shares Ross. When a company opts to pursue accreditation they are indicating a willingness to be honest and transparent with their business processes, procedures, outcomes and data. Accreditation, therefore, is necessary for this emerging industry. Having a robust, inclusive quality assurance system in place will ease and quicken their pursuit of accreditation.The stress on an audit day when there is a digitized system is vastly lower than a system that is printed and physically maintained.

Not all quality assurance systems are created equal. There are still some companies seeking to implement systems that lack the modernization necessary to truly propel them forward towards continuous improvement and scalability. Quality assurance software with widespread use and adaptation across organizations is both scalable and in support of continuous improvements. Binders, rows of filing cabinets and complicated excel spreadsheets are not a scalable backbone for a quality system. 

Beyond the accessibility and traceability that a digital system creates, it also protects. “We can protect that data with credentialed logins for key personnel and have information at our fingertips to reduce the regulatory stress on all personnel,” says Ross. The stress on an audit day when there is a digitized system is vastly lower than a system that is printed and physically maintained.

For those in the cannabis industry, specifically cannabis testing labs, there is an unequivocal advantage to implementing a system that supports continuous improvement, reliable data sets and the very best in business practices. Doing so will help sustain and grow the industry, and could be pivotal in transforming the production, market and research of cannabis.

Swetha Kaul, PhD

Colorado vs. California: Two Different Approaches to Mold Testing in Cannabis

By Swetha Kaul, PhD
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Swetha Kaul, PhD

Across the country, there is a patchwork of regulatory requirements that vary from state to state. Regulations focus on limiting microbial impurities (such as mold) present in cannabis in order for consumers to receive a safe product. When cultivators in Colorado and Nevada submit their cannabis product to laboratories for testing, they are striving to meet total yeast and mold count (TYMC) requirements.In a nascent industry, it is prudent for state regulators to reference specific testing methodologies so that an industry standard can be established.

TYMC refers to the number of colony forming units present per gram (CFU/g) of cannabis material tested. CFU is a method of quantifying and reporting the amount of live yeast or mold present in the cannabis material being tested. This number is determined by plating the sample, which involves spreading the sample evenly in a container like a petri dish, followed by an incubation period, which provides the ideal conditions for yeast and mold to grow and multiply. If the yeast and mold cells are efficiently distributed on a plate, it is assumed that each live cell will give rise to a single colony. Each colony produces a visible spot on the plate and this represents a single CFU. Counting the numbers of CFU gives an accurate estimate on the number of viable cells in the sample.

The plate count methodology for TYMC is standardized and widely accepted in a variety of industries including the food, cosmetic and pharmaceutical industries. The FDA has published guidelines that specify limits on total yeast and mold counts ranging from 10 to 100,000 CFU/g. In cannabis testing, a TYMC count of 10,000 is commonly used. TYMC is also approved by the AOAC for testing a variety of products, such as food and cosmetics, for yeast and mold. It is a fairly easy technique to perform requiring minimal training, and the overall cost tends to be relatively low. It can be utilized to differentiate between dead and live cells, since only viable living cells produce colonies.

Petri dish containing the fungus Aspergillus flavus
Petri dish containing the fungus Aspergillus flavus.
Photo courtesy of USDA ARS & Peggy Greb.

There is a 24 to 48-hour incubation period associated with TYMC and this impedes speed of testing. Depending on the microbial levels in a sample, additional dilution of a cannabis sample being tested may be required in order to count the cells accurately. TYMC is not species-specific, allowing this method to cover a broad range of yeast and molds, including those that are not considered harmful. Studies conducted on cannabis products have identified several harmful species of yeast and mold, including Cryptococcus, Mucor, Aspergillus, Penicillium and Botrytis Cinerea. Non-pathogenic molds have also been shown to be a source of allergic hypersensitivity reactions. The ability of TYMC to detect only viable living cells from such a broad range of yeast and mold species may be considered an advantage in the newly emerging cannabis industry.

After California voted to legalize recreational marijuana, state regulatory agencies began exploring different cannabis testing methods to implement in order to ensure clean cannabis for the large influx of consumers.

Unlike Colorado, California is considering a different route and the recently released emergency regulations require testing for specific species of Aspergillus mold (A. fumigatus, A. flavus, A. niger and A. terreus). While Aspergillus can also be cultured and plated, it is difficult to differentiate morphological characteristics of each species on a plate and the risk of misidentification is high. Therefore, positive identification would require the use of DNA-based methods such as polymerase chain reaction testing, also known as PCR. PCR is a molecular biology technique that can detect species-specific strains of mold that are considered harmful through the amplification and analysis of DNA sequences present in cannabis. The standard PCR testing method can be divided into four steps:

  1. The double stranded DNA in the cannabis sample is denatured by heat. This refers to splitting the double strand into single strands.
  2. Primers, which are short single-stranded DNA sequences, are added to align with the corresponding section of the DNA. These primers can be directly or indirectly labeled with fluorescence.
  3. DNA polymerase is introduced to extend the sequence, which results in two copies of the original double stranded DNA. DNA polymerases are enzymes that create DNA molecules by assembling nucleotides, the building blocks of DNA.
  4. Once the double stranded DNA is created, the intensity of the resulting fluorescence signal can uncover the presence of specific species of harmful Aspergillus mold, such as fumigatus.

These steps can be repeated several times to amplify a very small amount of DNA in a sample. The primers will only bind to the corresponding sequence of DNA that matches that primer and this allows PCR to be very specific.

PCR testing is used in a wide variety of applications
PCR testing is used in a wide variety of applications
Photo courtesy of USDA ARS & Peggy Greb.

PCR is a very sensitive and selective method with many applications. However, the instrumentation utilized can be very expensive, which would increase the overall cost of a compliance test. The high sensitivity of the method for the target DNA means that there are possibilities for a false positive. This has implications in the cannabis industry where samples that test positive for yeast and mold may need to go through a remediation process to kill the microbial impurities. These remediated samples may still fail a PCR-based microbial test due to the presence of the DNA. Another issue with the high selectivity of this method is that other species of potentially harmful yeast and mold would not even be detected. PCR is a technique that requires skill and training to perform and this, in turn, adds to the high overall cost of the test.

Both TYMC and PCR have associated advantages and disadvantages and it is important to take into account the cost, speed, selectivity, and sensitivity of each method. The differences between the two methodologies would lead to a large disparity in testing standards amongst labs in different states. In a nascent industry, it is prudent for state regulators to reference specific testing methodologies so that an industry standard can be established.

Microbiology 101 Part Two

By Kathy Knutson, Ph.D.
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Microbiology 101 Part One introduced the reader to the science of microbiology and sources of microbes. In Part Two, we discuss the control of microorganisms in your products.

Part 2

The cannabis industry is probably more informed about patients and consumers of their products than the general food industry. In addition to routine illness and stress in the population, cannabis consumers are fighting cancer, HIV/AIDS and other immune disorders. Consumers who are already ill are immunocompromised. Transplant recipients purposely have their immune system suppressed in the process of a successful transplant. These consumers have pre-existing conditions where the immune system is weakened. If the immunocompromised consumer is exposed to viral or bacterial pathogens through cannabis products, the consumer is more likely to suffer from a viral infection or foodborne illness as a secondary illness to the primary illness. In the case of consumers with weakened immune systems, it could literally kill them.Bacteria, yeast, and mold are present in all environments.

The cannabis industry shoulders great responsibility in both the medical and adult use markets. In addition to avoiding chemical hazards and determining the potency of the product, the cannabis industry must manufacture products safe for consumption. There are three ways to control pathogens and ensure a safe product: prevent them from entering, kill them and control their growth.

Prevent microorganisms from getting in

Think about everything that is outdoors that will physically come in a door to your facility. Control the quality of ingredients, packaging, equipment lubricants, cleaning agents and sanitizers. Monitor employee hygiene. Next, you control everything within your walls: employees, materials, supplies, equipment and the environment. You control receiving, employee entrance, storage, manufacturing, packaging and distribution. At every step in the process, your job is to prevent the transfer of pathogens into the product from these sources.

Kill microorganisms

Colorized low-temperature electron micrograph of a cluster of E. coli bacteria.
Image courtesy of USDA ARS & Eric Erbe

The combination of raw materials to manufacture your product is likely to include naturally occurring pathogens. Traditional heat methods like roasting and baking will kill most pathogens. Remember, sterility is not the goal. The concern is that a manufacturer uses heat to achieve organoleptic qualities like color and texture, but the combination of time and temperature may not achieve safety. It is only with a validated process that safety is confirmed. If we model safety after what is required of food manufacturers by the Food and Drug Administration, validation of processes that control pathogens is required. In addition to traditional heat methods, non-thermal methods for control of pathogens includes irradiation and high pressure processing and are appropriate for highly priced goods, e.g. juice. Killing is achieved in the manufacturing environment and on processing equipment surfaces after cleaning and by sanitizing.

If you have done everything reasonable to stop microorganisms from getting in the product and you have a validated step to kill pathogens, you may still have spoilage microorganisms in the product. It is important that all pathogens have been eliminated. Examples of pathogens include Salmonella, pathogenic Escherichia coli, also called Shiga toxin-producing E. coli (STEC) and Listeria monocytogenes. These three common pathogens are easily destroyed by proper heat methods. Despite steps taken to kill pathogens, it is theoretically possible a pathogen is reintroduced after the kill step and before packaging is sealed at very low numbers in the product. Doctors do not know how many cells are required for a consumer to get ill, and the immunocompromised consumer is more susceptible to illness. Lab methods for the three pathogens mentioned are designed to detect very low cell numbers. Packaging and control of growth factors will stop pathogens from growing in the product, if present.

Control the growth of microorganisms

These growth factors will control the growth of pathogens, and you can use the factors to control spoilage microbes as well. To grow, microbes need the same things we do: a comfortable temperature, water, nutrients (food), oxygen, and a comfortable level of acid. In the lab, we want to find the pathogen, so we optimize these factors for growth. When you control growth in your product, one hurdle may be enough to stop growth; sometimes multiple hurdles are needed in combination. Bacteria, yeast, and mold are present in all environments. They are at the bottom of the ocean under pressure. They are in hot springs at the temperature of boiling water. The diversity is immense. Luckily, we can focus on the growth factors for human pathogens, like Salmonella, pathogenic E. coli, and Listeria monocytogenes.

The petri dishes show sterilization effects of negative air ionization on a chamber aerosolized with Salmonella enteritidis. The left sample is untreated; the right, treated. Photo courtesy of USDA ARS & Ken Hammond

Temperature. Human pathogens prefer to grow at the temperature of the human body. In manufacture, keep the time a product is in the range of 40oF to 140oF as short as possible. You control pathogens when your product is at very hot or very cold temperatures. Once the product cools after a kill step in manufacturing, it is critical to not reintroduce a pathogen from the environment or personnel. Clean equipment and packaging play key roles in preventing re-contamination of the product.

Water. At high temperatures as in baking or roasting, there is killing, but there is also the removal of water. In the drying process that is not at high temperature, water is removed to stop the growth of mold. This one hurdle is all that is needed. Even before mold is controlled, bacterial and yeast growth will stop. Many cannabis candies are safe, because water is not available for pathogen growth. Packaging is key to keep moisture out of the product.

Nutrients. In general, nutrients are going to be available for pathogen growth and cannot be controlled. In most products nutrients cannot be removed, however, recipes can be adjusted. Recipes for processed food add preservatives to control growth. In cannabis as in many plants, there may be natural compounds which act as preservatives.

Oxygen. With the great diversity of bacteria, there are bacteria that require the same oxygen we breathe, and mold only grows in oxygen. There are bacteria that only grow in the absence of oxygen, e.g. the bacteria responsible for botulism. And then there are the bacteria and yeast in between, growing with or without oxygen. Unfortunately, most human pathogens will grow with or without oxygen, but slowly without oxygen. The latter describes the growth of Salmonella, E. coli, and Listeria. While a package seals out air, the growth is very slow. Once a package is opened and the product is exposed to air, growth accelerates.

Acid. Fermented or acidified products have a higher level of acid than non-acid products; the acid acts as a natural preservative. The more acid, the more growth is inhibited. Generally, acid is a hurdle to growth, however and because of diversity, some bacteria prefer acid, like probiotics which are non-pathogenic. Some pathogens, like E. coli, have been found to grow in low acid foods, e.g. juice, even though the preference is for non-acidic environments.

Each facility is unique to its materials, people, equipment and product. A safe product is made by following Good Agricultural Practices for the cannabis, by following Good Manufacturing Practices and by suppressing pathogens by preventing them coming in, killing them and controlling their growth factors. Future articles will cover Hazard Analysis and Critical Control Points (HACCP) and food safety in more detail.

Microbiology 101 Part One

By Kathy Knutson, Ph.D.
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I have been studying microorganisms for over 35 years, and the elusive critters still fascinate me! Here in Microbiology 101, I write about the foundation of knowledge on which all microbiologists build. You may have a general interest in microbiology or have concerns in your operation. By understanding microbiology, you understand the diversity of microorganisms, their source, control of microorganisms and their importance.

Part 1

The term microbiology covers every living being we cannot see with the naked eye. The smallest microbe is a virus. Next in size are the bacteria, then yeast and mold cells, and the largest microbes are the protozoans. The tiny structure of a virus may be important in the plant pathology of cannabis, but will not grow in concentrates or infused products. A virus is not living, until it storms the gate of a living cell and overtakes the functions within the cell. Viruses are the number one cause of foodborne illness, with the number one virus called Norovirus. Think stomach flu. Think illness on cruise ships. Viruses are a food service problem and can be prevented by requiring employees to report sickness, have good personal hygiene including good hand washing, and, as appropriate, wear gloves. Following Good Manufacturing Practices (GMPs) is critical in preventing the transfer of viruses to a product where the consumer can be infected.

The petri dishes show sterilization effects of negative air ionization on a chamber aerosolized with Salmonella enteritidis. The left sample is untreated; the right, treated. Photo courtesy of USDA ARS & Ken Hammond

The largest microbial cell is the protozoan. They are of concern in natural water sources, but like viruses, will not grow in cannabis products. Control water quality through GMPs, and you control protozoans. Viruses and protozoans will not be further discussed here. Bacteria, yeast and mold are the focus of further discussion. As a food microbiologist, my typical application of this information is in the manufacturing of food. Because Microbiology 101 is a general article on microbiology, you can apply the information to growing, harvesting, drying, manufacture of infused products and dispensing.

It is not possible to have sterile products. Even the canning process of high temperature for an extended time allows the survival of resistant bacterial spores. Astronauts take dehydrated food into space, and soldiers receive MREs; both still contain microbes. Sterility is never the goal. So, what is normal? Even with the highest standards, it is normal to have microbes in your products. Your goal is to eliminate illness-causing microorganisms, i.e. pathogens. Along the way, you will decrease spoilage microbes too, making a product with higher quality.

Petri dish containing the fungus Aspergillus flavus. It produces carcinogenic aflatoxins, which can contaminate foods and cause an invasive fungal disease.
Photo courtesy of USDA ARS & Peggy Greb.

Yeast and mold were discussed on CIJ in a previous article, Total Yeast & Mold Count: What Cultivators & Business Owners Need to Know. Fuzzy mold seen on the top of food left in the refrigerator too long is a quality issue, not a safety issue. Mold growth is a problem on damaged cannabis plants or cuttings and may produce mycotoxin, a toxic chemical hazard. Following Good Agricultural Practices (GAPs) will control mold growth. Once the plant is properly dried, mold will not grow and produce toxin. Proper growing, handling and drying prevents mycotoxins. Like mold, growth of yeast is a quality issue, not a safety issue. As yeast grow, they produce acid, alcohol and carbon dioxide gas. While these fermentation products are unwanted, they are not injurious. I am aware that some states require cannabis-infused products to be alcohol-free, but that is not a safety issue discussed here.

What are the sources of microorganisms?

People. Employees who harvest cannabis may transfer microorganisms to the plant. Later, employees may be the source of microbes at the steps of trimming, drying, transfer or portioning, extract processing, infused product manufacture and packaging.

Ingredients, Supplies and Materials. Anything you purchase may be a source of microorganisms. Procure quality merchandise. Remember the saying, “you get what you pay for.”

Environment. Starting with the outdoors, microbes come from wind, soil, pests, bird droppings and water. When plants are harvested outdoors or indoors, microbes come from the tools and bins. Maintain clean growing and harvesting tools in good working condition to minimize contamination with microbes. For any processing, microbes come from air currents, use of water, and all surfaces in the processing environment from dripping overhead pipes to floor drains and everything in between.

In Part 2 I will continue to discuss the diversity of microorganisms, and future articles will cover Hazard Analysis and Critical Control Points (HACCP) and food safety in more detail. What concerns do you have at each step of operations? Are you confident in your employees and their handling of the product? As each state works to ensure public health, cannabis-infused products will receive the same, if not more, scrutiny as non-cannabis food and beverages. With an understanding and control of pathogens, you can focus on providing your customers with your highest quality product.

Total Yeast & Mold Count: What Cultivators & Business Owners Need to Know

By Parastoo Yaghmaee, PhD
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Editor’s note: This article should serve as a foundation of knowledge for yeast and mold in cannabis. Beginning in January 2018, we will publish a series of articles focused entirely on yeast and mold, discussing topics such as TYMC testing, preventing yeast and mold in cultivation and treatment methods to reduce yeast and mold.


Cannabis stakeholders, including cultivators, extractors, brokers, distributors and consumers, have been active in the shadows for decades. With the legalization of recreational adult use in several states, and more on the way, safety of the distributed product is one of the main concerns for regulators and the public. Currently, Colorado1, Nevada and Canada2 require total yeast and mold count (TYMC) compliance testing to evaluate whether or not cannabis is safe for human consumption. As the cannabis industry matures, it is likely that TYMC or other stringent testing for yeast and mold will be adopted in the increasingly regulated medical and recreational markets.

The goal of this article is to provide general information on yeast and mold, and to explain why TYMC is an important indicator in determining cannabis safety.

Yeast & Mold

Photo credit: Steep Hill- a petri dish of mold growth from tested cannabis

Yeast and mold are members of the fungi family. Fungus, widespread in nature, can be found in the air, water, soil, vegetation and in decaying matter. The types of fungus found in different geographic regions vary based upon humidity, soil and other environmental conditions. In general, fungi can grow in a wide range of pH environments and temperatures, and can survive in harsh conditions that bacteria cannot. They are not able to produce their own food like plants, and survive by breaking down material from their surroundings into nutrients. Mold cannot thrive in an environment with limited oxygen, while yeast is able to grow with or without oxygen. Most molds, if grown for a long enough period, can be detected visually, while yeast growth is usually detected by off-flavor and fermentation.

Due to their versatility, it is rare to find a place or surface that is naturally free of fungi or their spores. Damp conditions, poor air quality and darker areas are inviting environments for yeast and mold growth.

Cannabis plants are grown in both indoor and outdoor conditions. Plants grown outdoors are exposed to wider ranges and larger populations of fungal species compared to indoor plants. However, factors such as improper watering, the type of soil and fertilizer and poor air circulation can all increase the chance of mold growth in indoor environments. Moreover, secondary contamination is a prevalent risk from human handling during harvest and trimming for both indoor and outdoor-grown cannabis. If humidity and temperature levels of drying and curing rooms are not carefully controlled, the final product could also easily develop fungi or their growth by-product.

 What is TYMC?

TYMC, or total yeast and mold count, is the number of colony forming units present per gram of product (CFU/g). A colony forming unit is the scientific means of counting and reporting the population of live bacteria or yeast and mold in a product. To determine the count, the cannabis sample is plated on a petri dish which is then incubated at a specific temperature for three to five days. During this time, the yeast and mold present will grow and reproduce. Each colony, which represents an individual or a group of yeast and mold, produces one spot on the petri dish. Each spot is considered one colony forming unit.

Why is TYMC Measured?

TYMC is an indicator of the overall cleanliness of the product’s life cycle: growing environment, processing conditions, material handling and storage facilities. Mold by itself is not considered “bad,” but having a high mold count, as measured by TYMC, is alarming and could be detrimental to both consumers and cultivators. 

Aspergillus species niger
Photo: Carlos de Paz, Flickr

The vast majority of mold and yeast present in the environment are indeed harmless, and even useful to humans. Some fungi are used commercially in production of fermented food, industrial alcohol, biodegradation of waste material and the production of antibiotics and enzymes, such as penicillin and proteases. However, certain fungi cause food spoilage and the production of mycotoxin, a fungal growth by-product that is toxic to humans and animals. Humans absorb mycotoxins through inhalation, skin contact and ingestion. Unfortunately, mycotoxins are very stable and withstand both freezing and cooking temperatures. One way to reduce mycotoxin levels in a product is to have a low TYMC.

Aspergillus flavus on culture.
Photo: Iqbal Osman, Flickr

Yeast and mold have been found to be prevalent in cannabis in both current and previous case studies. In a 2017 UC Davis study, 20 marijuana samples obtained from Northern California dispensaries were found to contain several yeast and mold species, including Cryptococcus, Mucor, Aspergillus fumigatus, Aspergillus niger, and Aspergillus flavus.3 The same results were reported in 1983, when marijuana samples collected from 14 cannabis smokers were analyzed. All of the above mold species in the 2017 study were present in 13 out of 14 marijuana samples.4

Aspergillus species niger, flavus, and fumigatus are known for aflatoxin production, a type of dangerous mycotoxin that can be lethal.5 Once a patient smokes and/or ingests cannabis with mold, the toxins and/or spores can thrive inside the lungs and body.6, 7 There are documented fatalities and complications in immunocompromised patients smoking cannabis with mold, including patients with HIV and other autoimmune diseases, as well as the elderly.8, 9, 10, 11

For this reason, regulations exist to limit the allowable TYMC counts for purposes of protecting consumer safety. At the time of writing this article, the acceptable limit for TYMC in cannabis plant material in Colorado, Nevada and Canada is ≤10,000 CFU/g. Washington state requires a mycotoxin test.12 California is looking into testing for specific Aspergillus species as a part of their requirement. As the cannabis industry continues to grow and advance, it is likely that additional states will adopt some form of TYMC testing into their regulatory testing requirements.

References:

  1. https://www.colorado.gov/pacific/sites/default/files/Complete%20Retail%20Marijuana%20Rules%20as%20of%20April%2014%202017.pdf
  2. http://laws-lois.justice.gc.ca/eng/acts/f-27/
  3. https://www.ucdmc.ucdavis.edu/publish/news/newsroom/11791
  4. Kagen SL, Kurup VP, Sohnle PG, Fink JN. 1983. Marijuana smoking and fungal sensitization. Journal of Allergy & Clinical Immunology. 71(4): 389-393.
  5. Centre for Disease control and prevention. 2004 Outbreak of Aflatoxin Poisoning – Eastern and central provinces, Kenya, Jan – July 2004. Morbidity and mortality weekly report.. Sep 3, 2004: 53(34): 790-793
  6. Cescon DW, Page AV, Richardson S, Moore MJ, Boerner S, Gold WL. 2008. Invasive pulmonary Aspergillosis associated with marijuana use in a man with colorectal cancer. Diagnosis in Oncology. 26(13): 2214-2215.
  7. Szyper-Kravits M, Lang R, Manor Y, Lahav M. 2001 Early invasive pulmonary aspergillosis in a leukemia patient linked to aspergillus contaminated marijuana smoking. Leukemia Lymphoma 42(6): 1433 – 1437.
  8. Verweii PE, Kerremans JJ, Voss A, F.G. Meis M. 2000. Fungal contamination of Tobacco and Marijuana. JAMA 2000 284(22): 2875.
  9. Ruchlemer R, Amit-Kohn M, Raveh D, Hanus L. 2015. Inhaled medicinal cannabis and the immunocompromised patient. Support Care Cancer. 23(3):819-822.
  10. McPartland JM, Pruitt PL. 1997. Medical Marijuana and its use by the immunocompromised. Alternative Therapies in Health and Medicine. 3 (3): 39-45.
  11. Hamadeh R, Ardehali A, Locksley RM, York MK. 1983. Fatal aspergillosis associated with smoking contaminated marijuana, in a marrow transplant recipient. Chest. 94(2): 432-433.
  12. http://apps.leg.wa.gov/wac/default.aspx?cite=314-55-102

Colorado Cannabis Lab Methods Updated for Microbial Testing

By Aaron G. Biros
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The Colorado Department of Public Health and Environment’s (CDPHE) Marijuana Laboratory Inspection Program issued a bulletin on January 30th regarding updates required for licensed cannabis testing labs. The updated method for microbial contaminant testing includes a longer incubation period in yeast and mold testing.BannerForEnf

“After careful consideration of emerging data regarding the use and effectiveness of 3M Total Yeast and Mold Rapid Petrifilms in marijuana, CDPHE has concluded that 48 hours is not a sufficient incubation period to obtain accurate results,” the letter states. “Based upon the review of this information, marijuana/marijuana products require 60-72 hours of incubation as per the manufacturer’s product instructions for human food products, animal feed and environmental products.” The letter says they determined it was necessary to increase the incubation period based on data submitted from several labs, along with a paper found in the Journal of Food Protection.

An incubator (Right) at TEQ Analytical Labs
An incubator (Right) at TEQ Analytical Labs

According to Alexandra Tudor, manager of the microbiology department at TEQ Analytical Labs (a cannabis testing lab in Aurora, CO), the update is absolutely necessary. “The incubation time extension requirement from CDPHE offers more reliable and robust data to clients by ruling out the possibility of a false yeast and mold result during analysis,” says Tudor.

Alexandra Tudor, microbiology department manager at TEQ Analytical Labs
Alexandra Tudor, microbiology department manager at TEQ Analytical Labs

“3M, the maker of Petrifilm, recommends an incubation time of 48-72 hours, but during TEQ’s method validation procedure, we learned that 48-hour incubation was not sufficient time to ensure accurate results. Although some laboratories in industry had been incubating for the minimum amount of time recommended by the manufacturer, the 48-hour incubation time does not provide a long enough window to ensure accurate detection of microbiological contaminants present in the sample.” Tudor says the update will help labs provide more confident results to clients, promoting public health sand safety.IMG_6386-2

As a result of the update in testing methodology, cultivators and infused product manufacturers in Colorado need to submit a batch test for yeast and mold. The point of requiring this batch test is to determine if the producer’s process validation is still effective, given the new yeast and mold testing method.