For any product consumed on a regular basis, contamination poses a health risk. Fungal species including molds and yeasts are common food and crop contaminants that can be harmful when inhaled, especially for those with compromised immune systems. Here we’ll explore how growers can reduce the amount of fungal formation in cannabis flower.

Cannabis Crops are Susceptible to Fungi

Processed foods and crops such as grains, beans, nuts, and fruits are susceptible to contamination. Cannabis is no exception.

Microbiological contamination includes a wide array of bacterial and fungal species. Many of these microorganisms are pervasive—even cannabis grown indoors with proper air filtration and good cleaning practices will be exposed to some level of microbiological contamination.

Cannabis is particularly susceptible to fungal contamination in the form of yeast and mold. These species can take hold under a wide range of temperatures and some flourish with relatively low water activity.

Most types of fungi are not infectious or toxic to humans. However, certain species pose a threat. For example, inhaling pathogenic forms of Aspergillus can cause an allergic reaction and respiratory infection. Medicinal users with compromised immune systems are especially vulnerable.

As a result, there’s a growing need among cannabis producers for an effective, post-harvest decontamination technique.

Testing New Ways to Eliminate Fungal Contamination

An obvious solution to stop the growth of fungus is to apply a chemical fungicide. However, the application of fungicides can leave behind harmful residues, creating yet another quality and safety concern.

In the food industry, manufacturers use ultraviolet germicidal irradiation as a safe and effective way to kill or inactivate microorganisms. Unfortunately, the most important compounds in cannabis, cannabinoids and terpenes, are sensitive to light and heat and may degrade when exposed to high-intensity UV light.

It’s clear that the cannabis industry could stand to benefit from new methods to prevent fungal colony growth that don’t expose cannabis flower to high temperatures, intense light, or chemical fungicides.

Recently researchers at the Volcani Center Agricultural Research Organization in Israel published a new study exploring ways to sterilize cannabis flower and remove fungal contamination.

They evaluated three different methods:

The researchers tested each method on samples of cannabis flower containing natural fungal contamination, some more than three times the limit set by the Israeli Medical Cannabis Agency (IMCA).

All of the methods reduced the number of fungal forming units (CFUs) per gram of cannabis flower to below the minimum standard of the IMCA. Gamma irradiation appeared to be the most successful and consistent method, reducing CFUs by up to 6-fold.

Keeping Your Cannabis Safe

Fungal contamination is a pervasive problem for cannabis growers. Preventative measures such as ventilation, proper cleaning protocols, and using dehumidifiers in damp areas are important, but fungal exposure can be hard to avoid. More aggressive sterilizing techniques help ensure fungal levels fall below the legal limits set by cannabis regulatory agencies like the BCC.

Are you looking for a quantitative microbial analysis of your cannabis? Encore Lab is an ISO/IEC 17025:2017 accredited testing lab that offers a full suite of cannabis testing including microbiological analysis. Contact us today to get started.