Did the Michigan Marijuana Regulatory Authority (MRA) ban molecular methods for microbial testing in 2021?
No, the MRA did not ban all qPCR tests for cannabis. In this article we aim to clarify misinformation surrounding cannabis testing in Michigan.
Did the Michigan Marijuana Regulatory Authority (MRA) ban qPCR?
- No. In January of 2021, the MRA issued a statement which temporarily "disallows the sole use of molecular methods such as qPCR for the quantification of total yeast and mold (TYM)”, based on preliminary data from the AOAC’s Emergency Response Validation (ERV) to address the MRA’s concerns over TYM testing. However, the MRA said it will reevaluate this decision as new information is gleaned from the ERV study. Unfortunately the MRA’s decision to change the requirements based on an incomplete study and in "an abundance of caution" has caused significant disruption to the sector.
- The January 2021 statement provides guidance for how Michigan labs that currently use qPCR should test for TYM going forward.
- It should be noted that the AOAC's ERV, and eventual SMPR, aims to evaluate TYM methods on cannabis flower only. The MRA's statement does not specify a matrix in their temporary disallowment of molecular methods, but it appears that molecular methods for testing marijuana infused products (MIPS) have been temporarily disallowed as well.
Does the MRA require labs to use AOAC certified methods?
- The MRA does NOT require a method to be AOAC certified. However, they make it very difficult to select a method outside of those that have received AOAC certifications. There are only AOAC SMPR's established for a select few targets and in some cases, only for certain matrices (flower). Search AOAC certified methods here.
- Due to the confusion with their messaging the MRA published a letter to all licensed laboratories in Michigan on April 16th, 2021. In it they clarify the following:
- All safety compliance facilities are required to employ the use of validated methods for all testing required by the agency in accordance with R 420.112(4)(b).
- Additionally, R 420.305(2) requires a laboratory to use analytical testing methodologies for required safety tests to be validated by an independent third party, and are subject to monitoring on an ongoing basis. In the absence of reference to compendia or published methods, Appendix K (or J where appropriate) of the AOAC must be published in full.
- When available, the standard method performance requirements (SMPRs) help to clarify the requirements of the validations. If the laboratory is running a method that has been appropriately validated or references a published method, the validation is expected to meet the targets (e.g. % recovery) outlined by the SMPRs. If the laboratory is seeking to pursue validation, either independently or with the assistance of a vendor, they must adhere to the published required analytical criteria.
- Changes to the Technical Guidance document are issued twice a year, with the expectation of compliance to the requirements outlined in the guide within 6 months from the date of publication. Version 3.0 of the Sampling and Testing Technical Guidance for Marijuana Products was released on February 11, 2021. Therefore, safety compliance facilities must comply with the changes outlined in this guide on or before August 11, 2021.
- All laboratories will receive updated method approval forms indicating any outstanding deficiencies. The laboratory is responsible for contacting their assigned LSS with any questions well in advance of the August 11, 2021 deadline for implementation of all changes.
What has MGC done to address the situation with total count tests in Michigan and other jurisdictions that may soon require AOAC Performance Tested Method certifications?
- Medicinal Genomics was a full participant in the AOAC Emergency Response Validation for Total Yeast and Mold in 2021. We launched our updated method for TYM in 2022 and received our AOAC PTM for the The PathoSEEK® Total Yeast and Mold qPCR Detection AssayTYM in 2024. This PTM certification is the first of its kind for a qPCR assay.
- The method launched in 2022 included improvements to our extraction method so we can lyse open more cells, improve genomic DNA recovery, and improve concordance with plating when compared with industry CRMs.
- It is important to note that the ERV study was at first designed with Potato Dextrose Agar (PDA) as a reference culture media, but shortly after our initial data was submitted we were notified that the reference method was changed. We immediately duplicated our efforts comparing PathoSEEK® to the new reference standard medium, Dichloran Rose Bengal with Chloramphenicol (DRBC), but this lead to a delay in new method development. Licensed testing laboratories in Michigan were also forced to validate new methods in accordance with this change.
Are there any changes coming to Medicinal Genomics' other total count assays?
- In an effort to make our assay concordant with plating techniques and with commercially available proficiency tests, we will continue to improve our methods to satisfy market and regulatory demands.
Problems Comparing qPCR to Plating
- The issue that we believe precipitated the MRA's actions started with a new NSI CRM for TYM proficiency testing in hemp matrices. This PT was developed for "culture methods" and does not produce qPCR results that are consistent with plating results.
- Our own investigation found that the NSI CRM for TYM (the emerald test panel) was ground to a fine powder, frozen, and contained cryopreservatives that are known to inhibit gDNA extraction.
- NSI has since updated their CRM and PT programs for hemp matrices to accomdate for the use of molecular assay methods.
- In general, this is not surprising since plating for “total” counts are inherently flawed and not comparable to qPCR results. Not all yeasts and molds grow in culture plates, but are picked up in qPCR. Bacteria often grow in TYM plates, but our assay is designed to exclude the bacteria. We write about this extensively in our help center:
