Beware of AOAC-Certified Claims for Cannabis Microbial Testing Methods

Note: This blog was originally posted in February 2019 and was updated in December 2020. 

The Association of Official Analytical Chemists (AOAC) publishes microbiological and chemical standards used globally to promote trade and to facilitate public health and safety. Testing labs trust AOAC-certified testing methods because they have passed a rigorous validation process and results have been repeated in multiple locations.

In 2019, the AOAC developed a Standard Method Performance Requirements (SMPR) for Aspergillus, E.coli, and Salmonella detection on cannabis. These are three separate SMPRs. In 2020, the AOAC also launched an Emergency Response Validation project for the enumeration of viable total yeast and mold in dried cannabis flower.

As of December 2020, only one microbial testing technology has completed the AOAC’s Perfomance Testied Methods (PTM) Program for detecting salmonella on cannabis and hemp flower. You can search all the PTMs on the AOAC website. 

But I received an email from another company that said their method is AOAC certified

Be careful. Some manufacturers are selling food safety testing methods to the cannabis market. Many of those methods are AOAC-certified for a variety of food types, but they have not been approved on cannabis.

If the method works on food, it will work on cannabis, right?

No. Anyone versed in cannabis testing can assure you, if you change the matrix, you must revalidate your technology. One cannot just superimpose the testing techniques from tomatoes onto Cannabis and assume the method’s function. One must revalidate their methods using a given technology on the new matrix. The superimposition of the methods that have been validated in the food industry onto a new matrix like cannabis is a major error and very misleading.

Is Medicinal Genomics applying for AOAC certification of its PathoSEEK assays?

Yes. We are delighted the AOAC has stepped in to manage the process for validating microbial detection technologies for cannabis. Without an industry-accepted benchmark, manufacturers have had to develop their own validation criteria, which can understandably raise doubts in skeptical customers’ minds. 

Our team is currently working on meeting the SMPR for Aspergillus and the Emergency Response Validation for Total Yeast and Mold (read more about our TYM validation work). We intend to meet and exceed all requirements set by the AOAC and expect that all our PathoSEEK assays will receive approval. 

Without AOAC certification, how do I know which method to trust?

Review the manufacturer’s validation data, and conduct your own validation.

The Medicinal Genomics team completed an extensive manufacturer’s validation, demonstrating our method for purifying DNA and detecting microbial contamination on cannabis flower, concentrates, and infused products meets the validation pillars of accuracy, precision, specificity, linearity and limit of detection.

Essentially the document proves:

All the experiments described in the document were conducted in the Medicinal Genomics laboratory, as well as several Independent Cannabis Testing Labs in Massachusetts. Several experiments used live pathogenic microbes and were conducted in Medicinal Genomics’ BioSafety Level 2 Laboratory.