WTF is irradiation?

Ashley Keenan
WTF is irradiation?

Irradiation has been a tense topic among Licence Producers (LPs) in cannabis since weed was legalized. Is it needed? Does it affect cannabinoids and terpenes? Is my weed radioactive? While the practice is a bit taboo, it’s estimated that 80-90% of cannabis producers in Canada are regularly irradiating their products.

What is irradiation?

Irradiation is the process of using radiation to destroy contaminants—such as bacteria, fungus, and mould— in a product. It’s not just cannabis that gets irradiated in Canada, the process is also used for dried spices and certain food products. For cannabis, irradiation is often used to meet Health Canada’s strict microbial limits because it is so effective at sterilization. However, the cannabis industry and consumers seem divided on whether or not it affects the quality of irradiated products. 


No, your weed isn’t radioactive

I hate to break it to you but lighting up irradiated cannabis isn’t going to make you into a weed-themed superhero like the radioactive spider who bit Peter Parker. Cannabis flower is typically irradiated with gamma rays, though electron beams and x-ray radiation can also be used. Emblem used the best analogy—when your personal items go through the x-ray machine at airport security they don’t come out the other end radioactive.

Gamma rays can be referred to as “cold pasteurization” or “electronically pasteurized” which carry less stigma and sound less severe than irradiation. Not all cannabis products are irradiated, it’s usually used on dried flower to avoid microbial contaminants. For instance, cannabis edibles aren’t irradiated; Health Canada only allows a handful of food products to be irradiated—potatoes, onions, flour, dried spices and seasoning mixes. These products are particularly sensitive to contaminants like mould spores. 

Why does irradiation get a bad rap?

Safety and stigma contribute heavily to irradiation's bad reputation and some arguments have merit. Comparing irradiation to putting your weed in the microwave is highly dramatic but that doesn’t mean there are no valid critiques of the process. 

Common Concerns:

  • Is irradiated cannabis safe for consumption?
  • Does irradiation kill terpenes and cannabinoids?
  • Does irradiated cannabis taste and smell the same?
  • How do I know if my weed is irradiated?

According to the SQDC, the provincial distributor for Quebec, irradiated cannabis is safe for humans as the levels of radiation used are insignificant for health. “Cannabis producers use irradiation for the same reasons agri-food producers do: to destroy potential bacteria, mould, and yeast, and to fight off possible parasite infestations. This method is currently the most effective, allowing producers to adhere to Health Canada’s strict safety measures.”

Cannabis producers use irradiation for the same reasons agri-food producers do: to destroy potential bacteria, mould, and yeast, and to fight off possible parasite infestations.

The main concern for consumers, aside from safety, is how irradiation affects terpenes and cannabinoids. There are those who insist irradiated weed tastes burnt and isn’t as potent. While more research is needed, there was a study in Frontiers of Pharmacology investigating exactly this. Researchers found that irradiation didn’t lower cannabinoid content, however, there was a “slight” reduction in terpenes. The study authors note the loss was comparable to leaving weed in a paper bag for a week.


Does legal cannabis need to be irradiated?

This is where things get a little complicated since irradiation isn’t required by Health Canada, leaving the choice to LPs. If growers don’t have to irradiate cannabis why would they choose to? Some LPs say irradiation is lazy and that proper growing practices negate the need for radiation treatment in the first place. While it can be difficult for large-scale producers to grow cannabis that doesn’t need to be irradiated, this is really where craft growers get to shine.

In addition to Canada, there are as many as 56 countries that use irradiation as a way to sanitize food and prolong shelf life. It’s worth noting that irradiation can actually be beneficial to some cannabis consumers, especially those using the plant for medicinal purposes. Patients are particularly vulnerable to contaminated products and allergens, so much so that the governments of Germany and the Netherlands both required medical cannabis to be irradiated.

While most cannabis consumers don’t really care about irradiation—or even know it exists—product transparency is crucial. Health Canada only requires edibles to include irradiation on the product label. However, some producers voluntarily share if the product is irradiated or not, allowing consumers to make the choice for themselves.


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