Marijuana Edibles and Cross-Contamination Risks

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Article contributed by Francine L. Shaw and Kimberley Stuck

As marijuana is being legalized in certain states, people are using it in many forms, including edibles.

Unfortunately, food safety isn’t always top-of-mind when preparing marijuana edibles, and if proper protocols aren’t followed, consumers can get very ill.

Cross-contamination is usually something that most people associate with foods, but it is also a real risk in the cannabis industry. Improper handling of cannabis and other ingredients can make consumers seriously ill, can cost companies millions of dollars in lost product, and can ruin organizations’ reputations. Companies that are involved in the cannabis industry should be aware of potential risks of marijuana edibles and always follow proper protocols to mitigate the risk of cross contamination.

Cross-contamination can happen in a number of ways in cannabis facilities. When growing cannabis, there are often issues involving pests, molds, and bacteria. Arrange regular visits from a pest control agency to manage pests, such as mice and gnats. Mice love cannabis as much as humans do, and if they get into your facility they will not only eat your plants, but will also contaminate product with their urine and feces. Mice are known to frequently carry salmonella bacteria in their digestive tract, so salmonella can be easily spread through contact with rodent waste. This is true with marijuana edibles just as it is with other food products.

Mold can be an issue as cannabis grows.  Powdery mildew (PM) is non-toxic and doesn’t produce mycotoxins (any toxic substance produced by a fungus), but it’s unsightly and can sometimes negatively affect the yield of the plant. Sometimes PM is tracked in from other sources on employees’ clothing.  It can also come from contaminated grow houses.  The flow of the facility is important to reduce or eliminate PM.  Additionally, prevent employees from going into a contaminated room and then going into a non-contaminated room.  This is essential to limiting PM/mold exposure.

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Pesticides are a risk factor in contaminating product.  If employees bring in plants that have been treated with pesticides, it can cross-contaminate clean plants.  Test plants – and their facilities – to determine whether pesticides were used before bringing treated plants into your clean facility.  Outdoor grows also run the risk of “drifting pesticides”. Know what neighboring crops are being sprayed with, and when they’re being sprayed.  This can help prevent cross-contamination with your clean crops.

Contamination often takes place in processing/manufacturing facilities. Contaminates can include pesticides, heavy metals, and toxins (such as arsenic), found in the oil used in the production of marijuana edibles.  This kind of contamination is most frequently seen in terpenes, essential oils, and sometimes CBD oil. It’s essential to conduct proper testing, evaluating all ingredients used in production. All manufacturing facilities must be aware of the sources and suppliers for the ingredients used in production, and take steps to mitigate these issues. As with processing of the food we consume daily, tracking the supply chain for cannabis is extremely important.

Do not allow employees to work when they’re ill, as illnesses can contaminate product, equipment and facilities. Implementing an employee illness policy is the best way to prevent illness from contaminating your manufacturing facility. Insist that employees utilize single-use gloves. Preventing bare hand contact of any marijuana edibles is also a great way to prevent contamination. Human hands can be the dirtiest things in your facility, so have proper hand washing procedures and proper PPE plans in place, and ensure that all employees comply with these protocols. Since there are no personal hygiene/health regulations in place for the cannabis industry at this time, we would suggest following those recommended by the current Food and Drug Administration (FDA) Food Code. 

Setting up proper sanitization is a must to prevent bacterial growth and cross-contamination. As in food preparation facilities, it’s essential to have proper handwashing stations in cannabis facilities.  Have hot water, soap, single-use paper towels, and a trash at each hand sink.  This promotes proper hygiene and assists with bacterial and mold spore elimination during hand washes.  Additionally, implement room sanitization after harvest, with mats in the entrance of rooms, and easily accessible sanitizer for tables and equipment.

Facilities should have designated areas for chemical storage. Improperly stored chemicals could possibly end up in the product, causing illness and even death in consumers. Train all employees to follow safe chemical storage protocols.

As with other types of cannabis facilities, dispensaries also deal with contamination. Often, dispensaries don’t properly clean bud jars between harvests. If a bud harvest is stored in a jar that has bacteria or mold contamination, and the jar isn’t cleaned/sanitized before the next clean bud is stocked, it can contaminate that next clean harvest, and the next, and the next. Having a proper cleaning and sanitation procedure can help prevent this form of cross-contamination. 

Don’t allow consumers or employees to touch cannabis items with their bare hands before purchasing or consuming product. This can easily cause the spread of bacteria to the product.

Proper protocols can save a business from recalls, consumer illnesses, and ruined reputations, ultimately leading to major profit losses and even the dissolution of the business.

The marijuana edibles business is not all that different from the food service industry. Consumers have the right to assume that the products they are purchasing are safe. It’s the manufacturer’s responsibility to do whatever it takes to ensure that it is.

Francine L. Shaw is President of Savvy Food Safety, Inc. which offers a robust roster of services, including consulting, food safety education, food safety inspections, crisis management training, writing norovirus policies for employees, writing norovirus clean-up procedures, curriculum development, responsible alcohol service training, and more. The Savvy Food Safety team has more than 100 combined years of industry experience in restaurants, casinos, and convenience stores and has helped numerous clients prevent foodborne illnesses. Francine has been featured as a food safety expert in numerous media outlets, including the Dr. Oz Show, the Huffington Post, iHeartRadio, Food Safety News, Food Management Magazine and Food Service Consultants Society International.  For more information, visit 

Kimberley Stuck, cannabis compliance expert and Founder of Allay Consulting, was the first Marijuana Specialist in the nation. She’s done everything from conducting compliance inspections, license sign offs, running pesticide investigations, conducting recalls, conducting shelf stability and CBD source approvals.  For more information, visit