Aspergillus is considered the number one Microbial Impurity of concern for the cannabis industry. Of the 11 species of Aspergillus, the State of California requires testing for four species deemed to be pathogenic: Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, and Aspergillus terreus. For Compliance Package I (Inhalable Cannabis) and Compliance Package II (Other Inhalable Cannabis Products) Aspergillus testing is required by the BCC. The concern is the inherent danger posed to patients or consumers through inhalation of product directly into the lungs. The heat generated through the combustion of the cannabis material does not reach the necessary heat to effectively eliminate all Aspergillus spores. Most healthy adults don’t seem to suffer from exposure to these spores, however for people with compromised immune systems, this can lead to a dangerous infection called “aspergillosis”. Edible or ingestible forms of cannabis however eliminate the risk of developing an Aspergillus infection, as the stomach acids and overall digestion process eliminate the organism and its spores. This is why Compliance Package III products are not required to undergo Aspergillus testing (i.e. edibles, tinctures, lotions, etc).
The testing for the four pathogenic Aspergillus species is very new; there are a small and limited number of commercially available test kits validated for Cannabis products. The best on the market are genetic based systems called Polymerase Chain Reaction (PCR) that can detect all four pathogenic species at one time, with additional confirmation testing required to determine the exact species.