Sampling cannabis or hemp for testing is a crucial part of the system that confers confidence to consumers purchasing those products. But, like much in the cannabis and hemp worlds, how cannabis and hemp cultivators select samples relies on an inconsistent patchwork of state laws.
ASTM International’s Committee on Cannabis aims to bring consistency to how cannabis and hemp growers collect, retain and send samples to state testing labs with a new standard.
“State-by-state requirements for batch testing (cannabis/marijuana focused) and sampling protocols vary significantly, if they exist at all,” David Vaillencourt, an ASTM member volunteer, recording officer for ASTM’s Cannabis Laboratory Subcommittee, and CEO and founder of The GMP Collective, told CBT/HG.
“There is ongoing frustration between cultivators and labs alike, which we have all seen [finger-pointing at each other] as to why lab-to-lab variability from the same flower batch continues to be a problem,” he continued. “Spoiler alert: There are multiple factors at play here, but the most fundamental one is the lack of ensuring a 'representative sample' has been collected from a batch.”
When cannabis or hemp farmers collect a sample for testing, “we need to make sure that when you send a sample in it's actually representative of the average,” Vaillencourt said. Cultivators (moreso those cultivating cannabis or hemp for cannabinoids) today have a financial incentive to send in a sample that will test as high as possible given that wholesale value is often directly tied to THC content. But, as Vaillencourt explained, farmers who cherry-pick samples like that might be reaping short-term gains while sowing long-term trouble.
“The reality is all you're doing is you're kicking the can down the road to when you get sued,” he said. “You can't just take one blueberry out of a whole field and say ‘that's representative.’”
“Cultivators of raw cannabis/hemp plants … require analytical test results designed to define the phytochemistry or level of impurities within a given post-harvest lot,” ASTM International member Cary Black, principal consultant and CEO of CK Black Group Inc., said in a statement. “The analytical results provide data indicating the conformity of the results within the guiding pharmacopeia or regulatory conditions of the final product.”
ASTM’s proposed standard on flower sampling, which is expected to be released in roughly six months pending unanimous approval from at least 60 percent the more than 900 Cannabis Committee members (who hail from 26 countries), would detail exactly how farmers should go about collecting samples for testing. The protocols would include steps on where to take samples from multiple locations across a field or room and from different parts of individuals plants, as well as how to ground and mix the samples to form a representative sample of the entire batch or field. It is only by milling and mixing the samples together than cultivators will be able to achieve an “average” representative sample, Vaillencourt explained.
“This standard establishes minimum requirements on how much biomass to collect to be able to mix so that you can have higher confidence that your numbers, within an average and acceptable range, are realistic,” Vaillencourt said.
Beyond helping achieve representative samples for product labelling, following ASTM standards can help cultivators defend themselves in legal proceedings by being able to prove that they followed protocols adopted by an agency with 120 years of experience in standards and unanimously approved by ASTM’s Cannabis Committee, Vaillencourt explained.
“I think it's important for folks to recognize the value of the concept of standardization,” he said. “You need to produce a repeatable, consistent product, and establishing standards and best practices is how you get there.”
ASTM’s Cannabis Subommittee on Laboratories also is developing 26 other standards which range from how to sample and test extracted products to how to store and test cannabis plant material for smoking use. All of the subcommittee’s standards, including those currently active, can be found here, and a complete list of ASTM’s Cannabis Subcommittees can be found here.