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The Challenges of Standardizing and Regulating Hemp Testing

By Kimberly Ross

Published: Dec 21, 2021   
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The current popularity of hemp-derived products, from textiles to tinctures, gummies to skin creams and more, bears witness to these rapidly growing sectors of manufacturing and commerce, while still operating under questionable legality in many parts of the globe.

The high demand for hemp-derived CBD for infused products in the US continues despite the Federal Drug Administration’s (FDA) position that CBD remains illegal as an ingredient in food, dietary supplements, animal feed, or for interstate commerce. In the absence of FDA oversight, the National Industrial Hemp Council of America (NIHC) has established its intention to introduce guidelines for hemp product quality testing, to support truth-in-labeling, and screen for contaminants such as pesticides and heavy metals.

Parallel frameworks for hemp product quality testing exist in state-mandated testing programs for medical and adult-use cannabis in the US, where testing is generally conducted by independent, accredited laboratories. The suitability of these frameworks for hemp quality control testing depends on the end-use of the product being tested. For example, industrial hemp grown for fiber and other textiles or building materials may not necessitate the battery of testing for high-CBD hemp flower intended for ingestion. From a public health perspective, hemp-infused products intended for ingestion should be screened for contaminants such as heavy metals, pesticides, mycotoxins, microbials, and residual solvents from extraction processes.

The cannabis industry has underscored the need for and efficacy of these testing regimes, given the failure rates of products in legal states found over-limit for regulated contaminants. The past decade of state-level cannabis testing programs in the US gives the hemp-infused product industry crucial information regarding quality control testing for these types of products. A notable recent investigation conducted by an Italian public health body indicated widespread presence of pesticides and heavy metals in “cannabis light”, the term coined for smokable hemp flowers. The authors highlight a need for greater oversight, calling for “actions [that] are needed to establish regulatory measures and reduce the adverse effects caused by contaminants in Cannabis”.

Refining the definition of hemp: is the 0.3 percent THC potency limit too restrictive?

In the US, The Agriculture Improvement Act of 2018 (the 2018 Farm Bill), Subsection G defined hemp to be crops and crop derivatives of the Cannabis sativa L. plant with an upper limit of 0.3 percent THC content by dry weight. Hemp, as defined by the Farm Bill, is thereby distinct from high-THC content plants of the same genus, commonly known as adult-use cannabis or marijuana. The Farm Bill goes a step further and requires “a validated testing methodology that uses post-decarboxylation or other similarly reliable methods” to determine total THC concentration levels of hemp produced in the state or territory.

Hemp farmers, however, are often dismayed just before harvest, when their crops test “hot”, i.e., when they test over the 0.3 percent threshold. In cases where there is no allowance for analytical uncertainty in the test method, or, for example, a reasonable buffer zone of up to 1 percent THC by dry weight, farmers risk ending up with a non-compliant crop at the culmination of a season’s worth of hard work and resource expenditures.

Elsewhere globally, hemp farmers struggle with low THC regulatory limits as well. In Europe, the total THC limit is set at only 0.2 percent in the crop. New legislation is expected to limit the detectable THC in any hemp-infused food product to 3.5 milligrams-per-kilogram (mg/kg), with hemp seed and oil up to 7.5 mg/kg, or less than 0.001 percent. Although still exceedingly low, this will actually represent an increase from the previous limit adopted by the European Food Safety Authority of 1 microgram-per-kilogram (0.0000001 percent). Ultra-low limits such as these can lead to unnecessary recalls, especially considering the analytical uncertainty associated with low analyte levels.

Independent analyses by multiple laboratories are likely needed to warrant a recall if such low limits persist in markets moving forward. Analytical accuracy and precision at such low levels needs careful validation and continual calibration verification of the instrumentation, with oversight by an accreditation body that has approved of the laboratory’s capabilities to perform this scope of testing.

Truth-in-labeling concerns: When CBD potency fails to meet label claims

The collective view from “secret shopper” testing campaigns conducted by news outlets and state agencies in the US has been clear: the hemp-derived CBD levels advertised on product labels do not necessarily live up to the stated potency when tested off-the-shelf by a third-party independent laboratory. Improved regulatory oversight will help the industry establish and maintain more accurate labeling standards. This is necessary to avoid further erosion of consumer confidence. Especially in the CBD-infused product markets, potency labeling is not necessarily required by an independent third-party lab. The manufacturer may conduct in-house testing for labeling purposes, and if not verified externally at least on a periodic basis, may be subject to bias (whether intentional or unintentional). Truth-in-labeling is crucial across all global markets, as consumers rely on this information when seeking an effective, reliable, and reproducible experience.

The rapid rise (and bans) of delta-8 tetrahydrocannabinol (d8-THC)

Delta-8-tetrahydrocannabinol (d-8-THC), like it’s more common isomer delta-9-tetrahydrocannabinol (d-9-THC), confers psychoactive effects when inhaled or ingested. CBD, abundantly present in hemp flowers, can be isolated from the plant biomass and then isomerized during the distillation process, yielding appreciable quantities of d8-THC. The oil extract is typically used to fill vape cartridges or to infuse delta-8 gummies, a popular form of edible now widely available. Almost half of US states have moved to enact bans on d8-THC products, while technically it exists in a federal gray area between hemp-derived cannabinoids legalized by the 2018 Farm Bill, and the Controlled Substances Act (CSA) of 1970, which designates THC a schedule I narcotic.

Screening for the presence of heavy metals is warranted

Heavy metals contaminants such as lead, arsenic, cadmium, and mercury have been flagged as a public health safety concern for cannabis and hemp. Action limits established for products in state-level cannabis markets in the US are similar to food safety levels, between 0.5 and 3 micrograms-per-gram (or parts per million, ppm). In Florida, the state’s food safety division has established regulations, including limits for metals specifically for extracts intended for ingestion.

Several potential sources for metals, such as lead, in hemp and cannabis products include the plant itself, an efficient bio-accumulator of environmental inputs, as well as consumer packaging of the final product. Shelf-life studies are a great tool to screen product as the consumer would obtain it, testing the same product periodically over time to identify any concerns, such as lead leaching into the oil, tincture, or other ingestible. It’s also important to establish in-process control points for all inputs, packaging materials, and environmental factors, in order to limit downstream risk of final product failure.

In Florida, for example, hemp extracts that are intended to be ingested are subject to food industry regulation, including those for packaging. The Florida Department of Agriculture and Consumer Services (FDAS) oversees food safety regulatory requirements, and now has jurisdiction over hemp-infused products manufactured in the state. It has investigated leaching of lead into products collected from the market and is seeing some cause for concern and continued monitoring of contamination of products on the market. It won’t be surprising to see shelf-life study requirements in final form packaging to validate materials that do not leach.

Responsible hemp cultivation must limit pesticide use

Regulations that limit pesticide residuals in hemp crops should be tied to the end-use of the finished product. Derived inhalable and ingestible products should be screened for extensive pesticide analyte lists, such as those currently required in California, Oregon, and Canada for adult-use cannabis. As mentioned, the cannabis genus of plants is known to be effective bio-accumulators, which can mean efficient uptake of pesticides sometimes already present in agricultural areas previously used for production of other crops. Notably, tolerances established for more traditional agricultural commodities, such as fruits, corn, wheat, etc., are based on metabolic elimination of these compounds by the human body when ingested; data are scarce to indicate appropriate tolerances for inhalation.

For industrial hemp crops whose end-products include building materials or textiles, every effort should still be made to limit widespread use of pesticides. With the potential to sow millions of acres with hemp, the best thing we can do is find sustainable, low-pesticide application methods of cultivation for the least impact on the environment.

California regulators plan to use a similar health-based approach to establish action levels for hemp based on proxy consumption rates and associated exposure to potential pesticide contaminants that were collected for cannabis regulatory statutes. In October of 2021, Bill AB-45 was signed into law in California, which created a legal pathway for the manufacture of infused foods, beverages, cosmetics, dietary supplements (and also pet food) derived from industrial hemp. The program will further establish the requirements for labels, barcodes/QR codes, or a manufacturer’s website link that provide expirations dates and potency data from laboratory certificates of analysis (COAs), indicating the THC content does not exceed 0.3 percent.

Microbials and mycotoxins

As with any botanical product, hemp flowers will naturally harbor microbial communities to some extent. During processing and curing, an appropriate environment must be maintained to limit any microbial growth once the plant is no longer alive, especially in the case of certain molds that can produce harmful mycotoxins as a byproduct of their metabolism (notably Aspergillus). A threshold such as 10,000 colony-forming-units per gram (CFU/gram) set forth by the United States Pharmacopeia (USP) is an appropriate pass/fail criterion for smokable flower. In the case of edible products, USP recommendations that limit the presence of E. coli and Salmonella are common sense in regulatory structure for hemp markets.

Solvents used in extraction of hemp biomass

Hemp biomass is commonly extracted to obtain more concentrated cannabinoids in forms such as oils and tinctures. These extracts are sometimes consumed by inhalation, and often infused into edibles, beverages and topicals. Similar to cannabis regulatory guidance, the presence of residual solvents from the extraction process should be limited for final products in the case of butane, propane, ethanol, and other hydrocarbon-based solvent extraction processes.

Greater regulatory oversight is warranted and welcomed for hemp markets

The fastest path toward reliability in hemp-derived CBD-infused product manufacturing is the widespread adoption of good manufacturing practices (GMP). A quality-centric approach that routinely screens inputs, processes, and environment helps establish reliability and reproducibility of the manufactured goods. The blueprints from other parallel manufacturing industries, including food, and pharmaceuticals, can offer a roadmap to getting this modern industry up to speed as quickly as possible while prioritizing public health safety.

Kimberly Ross

Chief Science Officer at Peak Compliance, LLC

Kim is the chief scientific officer at Peak Compliance, LCC, and has written for Analytical Cannabis on lab practices since 2019. She earned her PhD from the University of Colorado's Molecular, Cellular, and Developmental Biology program and is currently a contributing member to ASTM's D37 Committee for development of standards for cannabis products and processes and a participant in the Colorado Marijuana Enforcement Division's cannabis regulatory workgroup.


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