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Adulteration in the Hemp and Cannabis Markets

What is Adulteration?

There are many forms of adulteration and contamination that involve natural and artificial sources of hazardous substances. Adulteration refers to the willful or adverse manipulation of products meant for consumption. The issue of adulteration is widespread in industries meant for human consumption, which include food, dietary supplements, cosmetics, essential oils, and other botanical markets. According to Stefan Gafner, the chief science officer at the American Botanical Council, “adulteration happens in the botanicals market for reasons including supply chain shortages, the high cost of some botanical ingredients, and also the high volume of some ingredients” (Grebow, 2019). While adulteration is done to increase revenue, accidental contamination can also occur. This can include unknown toxins in the soil, pesticide drift from other farms, or mechanical issues during manufacture among other things. Unfortunately, it is common to find goods that are adulterated. Manufacturers employ tactics to save money and time on producing their wares. Additionally, some ingredients are not strictly regulated depending on their source of origin, which is often the case in the essential oil industry. There can also be an unfortunate case of human error, which occurs due to a lack of knowledge of certain processes or from unsanitary manufacturing conditions, both of which can lead to contamination. It can be extremely difficult to maintain sterile growing environments, however labs and manufacturing facilities are required to have standard operating procedures, which are documented process that lays out necessary steps in a task and also provides supporting information to help finish the task, in order to maintain cleanliness (Cohen & Ziskind, 2013).

Adulterants in the Supply Chain

As the public demands more cannabis and hemp products, the need for maintaining strict practices of cleanliness and lab testing increases greatly. Avoiding contamination at the initial step of the supply chain requires growers to ensure the soil is free from pesticides, heavy metals, and other natural sources of toxins. In order to produce a clean product, it must be grown without pesticides, fungicides, or growth enhancers. This is due to the fact that most natural contaminants appearing in this step could feature fungi, bacteria, and heavy metals which makes the product unsellable (National Academies of Sciences, Engineering, and Medicine, 2017). Another contamination source can show up during the drying process. The plant is releasing a significant amount of moisture as soon as it is harvested from the field. It is best to reduce half of the water content from the plants within the first 48 hours, which greatly reduces the conditions for bacteria and mold to grow (Cohen & Ziskind, 2013). Once the flower material or biomass is dried, the storage can also face a contamination risk depending on the temperature and humidity conditions. If growers take the time to properly ensure the climate conditions of the drying space, the final correct moisture content of the plant material, and that storage conditions are controlled, the issue of natural adulteration is reduced. The manufacturing process faces the most potential for adulteration, whether deliberate or unintentional. There can be solvent contamination caused by extraction processes, in addition to formulating with adulterated ingredients such as terpenes (from essential oils). Processors create infused goods for different delivery methods such as vape cartridges, infused food and beverages, and sublingual extracts (tinctures). Producers have to verify that they are sourcing high-quality ingredients and follow standard operating procedures to guarantee the product is both free from residual solvents and microbial contamination (National Academies of Sciences, Engineering, and Medicine, 2017).

How to Avoid Consuming Adulterated Products

In order for consumers to avoid purchasing products that contain contaminants is to make sure they do their due diligence by researching the product. By taking this step, one can feel satisfied that the company they are purchasing from lists the ingredients and is transparent about their process. Consumers can look for the company’s certificate of analysis (COA) which proves it was lab tested for cannabinoid content, pesticides, and other contaminants. If the information is available on the label or website, research where the flower material and other ingredients were sourced. Quality products come from companies that are transparent with their ingredients and how their hemp was grown. A good rule of thumb about purchasing is if the price is too good to be true, then it is. The price of CBD is going down, but quality CBD products will cost a little more due to the sourcing of high-quality ingredients such as organic oils and essential oils.

Suggested Solutions for the Supply Chain

It is beneficial for growers and manufacturers to be knowledgeable about sources of adulteration so they can avoid the risks. Growers should use only organic growing methods and supplements, as well as testing the soil before planting their crops. Additionally, employing integrative pest management methods would be beneficial to avoid having to use pesticides. Manufacturers should source only quality, trusted ingredients and suppliers for the terpenes and other formulation ingredients. People who are working throughout the supply chain would be remiss if they didn’t educate themselves on the cultivation methods, plant phytochemistry, and manufacturing processes. Standard operating procedures are crucial to have in place because they standardize best practices in an organization and ensure that all personnel are following the same proven methods (Stuck, n.d.). Having knowledge of the plant and the industry as a whole benefits everyone involved as it reduces errors of natural and artificial adulterants. It is important that we continue to find ways of providing hygienic standards throughout the supply chain otherwise we will continue to see adulterated cannabis and hemp products.


Cohen, M., & Ziskind, J. (2013). Preventing Artificial Adulterants and Natural Contaminants in Cannabis Production: Best Practices (Rep.). Retrieved

Dryburgh, L. M., Bolan, N. S., Grof, C. P., Galettis, P., Schneider, J., Lucas, C. J., & Martin, J. H. (2018). Cannabis contaminants: Sources, distribution, human toxicity and pharmacologic effects. British Journal of Clinical Pharmacology, 84(11), 2468-2476. doi:10.1111/bcp.13695

Grebow, J. (2019). 2019 Ingredient trends to watch for food, drinks, and dietary supplements: Adulteration Risk. Nutritional Outlook. 37-40.Retrieved from

National Academies of Sciences, Engineering, and Medicine. (2017). Chapter 2 Cannabis. In The health effects of cannabis and cannabinoids: The current state of evidence and recommendations for research (pp. 43-60). Washington, DC: The National Academies Press.

Schmidt, E. (n.d.). Summary of Adulteration of Essential Oils Chapter from Handbook of Essential Oils, 2nd Edition. Retrieved from

Stuck, K. (n.d.). Food Safety Solutions for Edible Cannabis: Contamination, Sourcing and SOPs. Retrieved from



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