How Are Microorganisms and Mycotoxins Detected in Cannabis?

Medical cannabis offers an array of therapeutic benefits, from managing pain and inflammation to treating conditions like depression, anxiety and PTSD. While the plant has powerful medicinal properties, it’s also at risk of contamination from microorganisms and mycotoxins. Laboratory testing and analysis plays an important role in detecting these contaminants and determining if medical cannabis is safe for consumption.

A closer look at medical cannabis contaminants  

Mould, mildew, bacteria and yeast are just some of the microorganisms that can develop in medical cannabis crops and products. Cannabis is also vulnerable to fungal toxins such as mycotoxins and aflatoxins.

Detecting microorganisms and mycotoxins in cannabis

Below, we take a closer look at some of the most common methods used to detect and quantify microorganisms and mycotoxins in medical cannabis.

• Microscopic observation

A dissecting microscope is one of the easiest, cheapest and more cost-effective methods for detecting microorganisms and mycotoxins in cannabis. After sample preparation is complete, cannabis is simply placed under the lens, which allows scientists to visually detect contaminants such as mould and mildew. While useful for some applications, a dissecting microscope doesn’t offer the same insight as methods such as Polymerase Chain Reaction (PCR) testing.

• PCR testing

Used to detect genetic material, PCR testing is used to identify unique bacterial strains and toxins in cannabis samples. Also known as molecular photocopying, the technique takes a small DNA sample and multiplies it to create enough material for detailed genetic and molecular analysis.

• Petri film analysis

Petri film analysis is another simple and effective way to detect microorganisms and mycotoxins in cannabis. The traditional microbiology technique does have its merits though some experts warn it’s unsuitable for cannabis testing. In a study published on the F1000Research platform, a team of scientists found culture-based techniques don’t offer the same accuracy, precision and repeatability as genetic sequencing technology. This not only risks the integrity of the medical cannabis industry but puts consumers at risk.

“Samples subjected to culture showed substantial shifts in the number and diversity of species present, including the failure of Aspergillus species to grow well on either platform,” reads the abstract. “Substantial growth of Clostridium botulinum and other bacteria were frequently observed on one or both of the culture-based TYM platforms. The presence of plant growth promoting (beneficial) fungal species further influenced the differential growth of species in the microbiome of each sample.”

Along with microorganisms and mycotoxins, medical cannabis laboratories test extensively for heavy metals, pesticides and other contaminants. Find out more about the advanced techniques and technologies used across the industry in ‘Medical Cannabis - Testing, Analysis & Identification’.