Listeria is a gram-positive, rod-shaped bacterium that is found in contaminated foods. Listeria can be found in soil, which can lead to plant contamination. Animals who eat contaminated vegetation can become carriers. Therefore, for obvious reasons the bacterium has also been found on and in a variety of food types including meats, dairy products, fruits, and vegetables.

Why is Listeria dangerous to cannabis users?


The subspecies L. monocytogenes is a major human pathogen that can cause listeriosis, a rare bacterial disease with a 20% case-fatality rate. Pregnant women, newborns, the elderly, and immunocompromised adults are at the greatest risk of developing listeriosis.

According to the CDC, listeriosis is usually a mild illness for pregnant women, but the fetus or newborn baby can develop a severe disease. Adults 65 years and older and people with weakened immune systems, can develop severe infections of the bloodstream (causing sepsis) or brain (causing meningitis or encephalitis).

To date, there have been no documented cases patients contracting Listeria from contaminated cannabis, but given the fact that the bacterium is found in soil, the cannabis plant could very well be at risk. And depending on how that plant is processed and ingested, certain populations could also be at risk.