Dear Agricor Laboratories Customer,

On Monday, December 5th, the CDPHE announced to all marijuana testing laboratories that those using the 3M Rapid Yeast and Mold Petrifilms are no longer allowed to insufficiently complete their incubation in 48 hours. Rather, the CDPHE now recognizes proper incubation times of 60 – 72 hours, which is consistent with 3M’s validated data.

The CDPHE investigated the reliability of the data generated from marijuana laboratories who are incubating at 48 hours and compared that with other industries using the same 3M Rapid Yeast & Mold Petrifilm product.  They also cited an independent scientific journal article published in 2016 demonstrating the inadequacy of a 48 hour incubation time.*  The CDPHE’s conclusion was that 48 hours is insufficient, which is consistent with the 3M’s validated data.

In anticipation of this new requirement, we are changing nothing. Agricor Laboratories has been executing our Total Yeast & Molds test correctly from Day 1, according to the manufacturer’s recommended procedures and according to good scientific processes. Our microbial contaminants test method was validated to industry standards, consistent with all other Agricultural, Food, and Pharmaceutical industry standard practices.

As regulations and other laboratories strive to make corrections to catch up to industry standards, Agricor Laboratories will continue to set the bar in Cannabis testing and provide you with confidence in your test results, thereby eliminating repeat testing.

Rest assured that there will be absolutely no impact for those who have used Agricor for the entirety of their microbial process validation. If you have conducted your Microbial Contaminants process validation using Agricor Laboratories, you will not have to repeat the process validation.  You should expect:

  • No change in your reported levels of Total Yeast & Mold.
  • No change in your turn around times.
  • No change in your Process Validation.

For more information, call our support line at (720) 460-3489.

* Journal of Food Protection, “Comparison of New and Traditional Culture Dependent Media for Enumerating Foodborne Yeasts and Molds.


After careful consideration of emerging data regarding the use and effectiveness of 3M Total Yeast and Mold Rapid Petrifilms in cannabis, it has been concluded that 48 hours is not a sufficient incubation time to achieve accurate counts. This determination was based upon several factors, including data obtained by several testing facilities, as well as the Journal of Food Protection 2016 paper “Comparison of New and Traditional Culture-Dependent Media for Enumerating Foodborn Yeasts and Molds,” which show clear differences between rapid films and comparative methods (DRBC, ADPA) at the 48 hour vs. the 72 hour endpoint. Based upon the reviewed information, it is concluded that cannabis and cannabis products fall into the category of matrices which require 60-72 hours incubation as per the manufacturer’s product instructions for human food products, animal feed and environmental products. Please make the appropriate adjustments to any laboratory procedure that requires 48 hours incubation as the minimum time for rapid yeast and mold petrifilms.