Automated image analysis with ImageJ of yeast colony forming units from cannabis flowers

Publication date: Available online 2 August 2019Source: Journal of Microbiological MethodsAuthor(s): Nicholas Stolze, Carly Bader, Christopher Henning, Jared Mastin, Andrea E. Holmes, Arin L. SutliefAbstractCurrently, in the state of Colorado and all other states within the United States of America with legalized marijuana programs, testing is required for bacteria, yeast, and mold on marijuana products. The Code of Colorado Regulations, 1 CCR 212–1, considers a passing result when a 1 g sample contains <104 colony forming units (CFU) for the total yeast and mold count (TYMC). These measurements are usually obtained by manually counting colonies on petri-dishes or 3 M™ Petrifilms™, which is a time consuming and user subjective process. Therefore, an automated counting method utilizing ImageJ has been developed for CFU analysis of TYMC on Petrifilms. The performance of this colony counting method was demonstrated by comparing manual and automated counts from marijuana flower samples containing spikes of Candida albicans as well as samples that tested positive for the presence of yeast and mold. Fifteen images of Petrifilms showing various concentrations of colonies were studied by fifteen users at two institutions using both the automated and manual counting methods. All counts from the automated ImageJ procedure were within 12% of those obtained manually. In twelve out of fifteen Petrifilms, the average count of the automated method was statistically similar to ...
Source: Journal of Microbiological Methods - Category: Microbiology Source Type: research