Cannabis is a relatively new part of the well-established agriculture industry and brings with it novel challenges to assure that its use in foods and drinks for medicinal and recreational purposes will be safe for consumers. Businesses are showing a lot of interest in using various parts of the cannabis plant in edibles and beverages, including Ben & Jerry’s, which said in 2019 that it planned to offer a cannabis-infused ice cream. U.S. sales of drinks infused with cannabidiol (CBD), a non-intoxicating chemical obtained from hemp, are expected to grow to more than $1.4 billion in 2023, up from $86 million in 2019, according to researcher Zenith Global’s Beverage Digest. That’s on top of sales of medical and other cannabis edibles.
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Explore This IssueJune/July 2020
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Hemp and marijuana are in the same cannabis plant family, Cannabis sativa. The difference between them lies in the amount of the psychoactive ingredient tetrahydrocannabinol (THC) that they can contain. A key issue in widespread adoption of cannabis-infused products is that, on a federal level, cannabis and CBD-infused foods still aren’t legal. That’s partly due to health and safety concerns such as potential liver injury, drug interactions, male reproductive toxicity, and side effects such as drowsiness.
States where cannabis is legal each have their own requirements for product testing and remediation. That means a mold or yeast level in a cannabis flower may be acceptable in one state but not another. Mold and yeast are two of the main culprits causing cannabis products to fail a state safety test, but laboratories also test for other microbes, mycotoxins, pesticides, heavy metals, water content, residual solvents, and terpenes, which are the flavor and scent components of cannabis.
“A lot of regulations have been made in a very short period of time that aren’t really based on too much scientific fact,” says Ketch DeGabrielle, a cannabis consultant with Qloris Consulting in Boise, Idaho. Formerly, DeGabrielle was operations manager at Los Suenos Farms, a large-scale cannabis farm in Avondale, Colo. He specializes in designing harvest and processing systems.
DeGabrielle says that most states look at total numbers of yeast and mold in cannabis. However, some yeasts live compatibly with the cannabis plant and keep dangerous molds from taking hold, he adds. “So, looking at everything in totality, we’re not really getting a whole picture that way,” he says. “We’re just saying it can’t have ‘x’ amount of a certain fungus.” But not all fungi or bacteria are harmful or will cause a health problem if infused into food or drinks.
Any moist cannabis plant can develop yeast or mold, just like other agricultural products, he says. When the cannabis plant is harvested, the bud or flower is wet, and it’s important to lower the moisture content within seven days after harvesting. Cannabis and hemp are dried in different ways because the sun degrades the THC potency and heat can diminish the taste and scent of the plant’s terpenes.
Some states also test for Aspergillus, Salmonella, and E.coli, which DeGabrielle says is good practice because those microbes are all dangerous to people. But he and others say more specific testing of microbials needs to be done.
The Cannabis Microbiome and Testing
Brianna Cassidy, PhD, an analytical chemist at CDX Analytics, a cannabis testing laboratory in Salem, Mass., says there’s a lack of knowledge of what is actually present in the microbiome of cannabis, because it is comparatively recent to the agriculture industry. “It can host a plethora of different microorganisms, but there’s only been a few decades for this plant to be heavily studied,” she said. “So, we have to figure out what living things are present that need to be tested for.”
Two main testing methods currently are used for cannabis: DNA-based and growth-based methods. Growth-based methods involve plating so the microorganisms on the product can be grown, seen, and counted. The process can take weeks, but it is the gold standard in agriculture, Dr. Cassidy says.
Still, because it takes a while to grow microbes, that method has its limitations, she says. DNA-based methods are faster because they can detect microorganisms without requiring them to grow. “What we are doing is cracking open the cells of these microorganisms, getting the DNA, and quantifying it using fluorescence technology, which is extremely sensitive,” she says. CDX Analytics also tests for 12 cannabinoids.
Massachusetts, where her company is based, requires certain tests at certain parts of the process. While a plant-infused product will be tested for potency, microbials, and mycotoxins, the plant itself will be tested for those three plus metals. “We see a lot fewer microbes on processed products than we do on raw plant materials,” Dr. Cassidy says. “When you use an extraction process on a living plant the heat process helps kill any microbes that were present.”
If a test fails, the cannabis grower can have the product retested or remediated. Remediation options include using light or ozone treatments or extracting the cannabinoids from the plant, she says.
Some growers choose to conduct their own pretests before submitting their product to a lab like CDX Analytics, which adheres to state testing requirements. “Our tests are being used in testing labs, but some growers are also buying our products now so that they can do a pretest before they send it out to be tested,” says Heather Ebling, senior applications and support manager at Medicinal Genomics, a Beverly, Mass., company that makes quantitative PCR tests for testing labs to isolate DNA from a cannabis flower.
She says the pretests are a “heads up” as to whether or not the cannabis is going to pass, and if it’s not, to conduct some remediation to decrease the number of microbes that are present. “Once you get a failing test you can actually ruin a whole batch or crop. It’s pretty detrimental,” Ebling says. “Some states do allow remediation and they’ll let growers have a second chance.”
Like others in the cannabis industry, she recommends more species-specific testing of mold, yeast, and other microbes.
In Massachusetts the limit for a total yeast and mold test is 10,000 colony forming units (CFUs) per gram, she says. “So you could have 9,000 CFUs of Aspergillus and it still will pass,” she says. “But you don’t know if its Aspergillus because while the microbe is triggering your total yeast and mold test, the test isn’t telling you what the microbe is.”
There are many products and techniques on the market that can help with remediation. Some are used as preventive measures, as a last step before the cannabis is tested. Others are used after a test fails.
The most common and cost-effective technique is to process the plant and extract the THC or CBD or both, says DeGabrielle. “That removes everything except the desired elements from the plant materials,” he says. “Using fractional distillation, you can essentially remove impurities.” It’s a common technique in any type of agricultural product extraction, he adds.
Willow Industries, a Denver, Colorado-based cannabis remediation and decontamination company, sells systems that use ozone to mitigate mold and bacteria by essentially introducing a kill step. “Cultivators typically implement our technology as the last step in their production process, and then they send the product out to be tested to the licensed lab,” says Jill Ellsworth, founder and CEO of Willow Industries. She says the ozone gas degrades microbial contaminants on the product.
The company’s product treats only the flower, which is the raw product, before it is tested to ensure there are no pathogens remaining and that it will pass testing.
Other companies use other gases. For example, ClorDiSys of Somerville, N.J., uses chlorine dioxide gas and ultraviolet light to decontaminate all or part of a contaminated grow facility. Grow rooms, for example, are common locations for mold to spread from plant to plant, according to the company’s website.
DeGabrielle recommends buying cannabis products from reputable companies that use testing labs. “With no federal guidance or oversight, consumers need to research their state’s testing and see if it protects them. If not, they should advocate with the state for better testing,” he says. “We need to develop systems and techniques that keep things from happening. We’ve successfully done that with pretty much every agricultural product we consume.”