Matrix Extension of the CompactDry™ “Nissui” YMR for Enumeration of Yeasts and Molds in Dried Cannabis Flower: AOAC Performance Tested MethodSM 092002

Background: CompactDry™ Yeast/Mold Rapid (YMR) is a ready to use dry media sheet using a chromogenic medium with selective agents for the enumeration of yeasts and molds in a variety of food products after incubation at 25 ± 1 °C for 3 days. The method is certified as AOAC Performance Tested MethodSM 092002.

Objective: The CompactDry YMR method was validated for a matrix extension to cannabis flower through the AOAC Emergency Response Validation process.

Methods: The performance of the CompactDry YMR was compared to Dichloran Rose Bengal Chloramphenicol (DRBC) agar for the enumeration of yeasts and molds in cannabis flower. Matrix data were normalized by log10 transformation and performance indicators included repeatability, difference of means (DOM), and inclusivity/exclusivity.

Results: The results demonstrated that the CompactDry YMR method is equivalent to the DRBC agar method at 72 hours of incubation. In the independent laboratory validation study, there was no significant difference in detection, enumeration, or repeatability between the CompactDry YMR method and DRBC agar at 72 hours. Eighteen inclusivity and 16 exclusivity strains specific to cannabis plant materials that were not evaluated in the original CompactDry YMR method validation were tested in this study. All inclusivity organisms produced typical colonies on the CompactDry YMR. The two exclusivity bacterial strains that showed growth on CompactDry YMR at 72 hours were inoculated at a high concentration.

Conclusion: CompactDry YMR is equivalent in performance to traditional culture media detection methods of yeasts and molds. Highlight: CompactDry YMR will streamline dried cannabis flower testing.