Cannabis-Infused Edible Products in Colorado: Food Safety and Public Health Implications

Alice E. White, MS; Christine Van Tubbergen, MPH; Brianna Raymes, MPH; Alexandra Elyse Contreras, MPH; Elaine J. Scallan Walter, PhD


Am J Public Health. 2020;110(6):790-795. 

In This Article

Food Safety Hazards

The production of any cannabis-infused edible food product includes cultivating the cannabis plant, processing plant material to extract concentrated oils, manufacturing the food, and infusing concentrated cannabis oil into the food. Each step in this process is subject to potential food safety hazards (Figure 1). Additionally, there are food safety risks associated with noncannabis ingredients.

Figure 1.

Cannabis Edibles Processing and Associated Hazards

Similar to other plants grown indoors, cannabis plants can potentially be exposed to a variety of food safety hazards, including contamination by metals, pesticides, molds, fungi, mites, and microbial pathogens, some of which are naturally occurring in the environment. Concentrated oils containing tetrahydrocannabinol (THC), cannabidiol, and other cannabinoids are extracted from raw plant material using solvents such as hydrocarbons and ethanol.[3] Thus, concentrated cannabis oils may retain solvent impurities or residual solvents and could potentially contain concentrated amounts of contaminants; for example, a study in Oregon found detectable pesticides in 55% of cannabis concentrate samples (vs 29% of flower samples), with 46% failing Environmental Protection Agency tolerances.[11]

Heat is required to decarboxylate tetrahydrocannabinolic acid (THCA) to its psychoactive form (i.e., THC), which can be done before food processing or during food processing, depending on the product. Cooking at an ambient temperature of approximately 220°F for 30 to 45 minutes is required to activate THC. Heating above the minimum THC temperature may cause some degradation to the THC, so producers may be incentivized to cook at lower temperatures, which may not meet minimum internal temperatures to kill microbial contaminants; for example, the US Department of Agriculture recommends that low-acid foods be heated to 240°F to 250°F to destroy Clostridium botulinum spores.[12]

In Colorado, food products are manufactured by licensed medical marijuana–infused product manufacturers or retail marijuana product manufacturers. Colorado's cannabis rules prohibit manufacturers of edibles from using a commercially manufactured food product. The Colorado code and regulations for medical and retail marijuana edible production requires owners or licensees of manufacturing facilities to take a food safety course and to

comply with all kitchen-related health and safety standards of the relevant local jurisdiction and, to the extent applicable, with all Colorado Department of Public Health and Environmental Health (CDPHE) health and safety regulations applicable to retail food establishments. [13]

However, enforcement of these regulations is variable; for example, Denver is the only jurisdiction in Colorado that enforces food safety regulations with routine regulatory food safety inspections at all dispensaries and edible manufacturers every six months.

In Colorado, samples of edible products are collected internally by the manufacturer and test batches are sent to external laboratories for testing of potency, mycotoxins, total yeast and mold, residual solvents, metals, pesticides, Shiga toxin–producing Escherichia coli, and Salmonella.[13] The testing of pathogens and residues remains a challenge, as does the development of extraction methods for the vast variety of edible products. To varying degrees, largely dependent on the state, limitations of laboratory testing persist, including nonstandardized protocols, inability to identify the source of a positive test (cannabis oil vs food ingredient), lack of access to testing, insufficient licensed laboratories to meet testing volume, inadequate methods for THC extraction from all potential edible food matrices, and testing accuracy not independently validated by state regulators.[14,15]

Edibles are labeled, packaged, and delivered to medical or retail dispensaries, where they are sold to consumers. In Colorado, labeling requirements include the universal symbol, ingredient list, statement regarding refrigeration, statement of production date, statement of expiration date, nutrition facts panel, serving size, and total active THC statement. Storage at the production facility, retail store, or consumer's home may affect the potency, quality, and safety of an edible product.[15,16] For example, improper ventilation can result in humid conditions and mold growth.[16] Finally, there are potential hazards associated with individual use, including unintentional consumption, overconsumption, and off-label use.

Although some edible products are inherently lower risk because of their low-water activity, high acidity, or fermentation (e.g., baked goods), other products with low-acid and high-water activity (e.g., foods requiring refrigeration), as well as ready-to-eat foods, present a greater food safety risk. In addition, extractions used in edible products often have an oil, glycerol, or glycol base in which anaerobic pathogens, such as C. botulinum, can thrive if not prepared and stored properly.[17,18]

The National Environmental Health Association developed guidance for cannabis food safety programs that summarizes regulations in states with legalized cannabis to address the hazards we have described. Food safety considerations include storage legislation for all production stages (e.g., cultivation, production, distribution, testing, and sale); standardized collection and testing methods at multiple production stages for potency, homogeneity, residual pesticides, cannabinoids, metals, microbials, mycotoxins, moisture content, and water activity; labeling and packaging regulations; training and education, including required food-handling certification; and food safety plans, including required hazard analysis critical control point plans, standard operating procedures, inspection requirements, and recall plans.[16]