Validation of the Soleris® NF-TVC Method for Detection of Aerobic, Mesophilic Microorganisms in Dried Cannabis Flower: AOAC Performance Tested MethodSM 071203.

Background: Soleris® Non-Fermenting Total Viable Count (NF-TVC) is a growth-based, automated method for semiquantitative detection of aerobic, mesophilic microorganisms in foods and other consumer products such as nutraceuticals and cosmetics. The method was granted AOAC Performance Tested MethodSM status for select foods after successful completion of a validation study.

Objective: The objective of the current study was to validate the Soleris NF-TVC method for use with dried cannabis flower [>0.3% delta 9-tetrahydrocannabinol (THC)].

Methods: The validation consisted of a comparative matrix study in which naturally contaminated dried cannabis flower was tested with the Soleris NF-TVC method and with the AOAC Official Methods of AnalysisSM  966.23 dilution plating method. Multiple lots of dried cannabis flower were obtained, pre-screened for total aerobic, mesophilic viable count levels, and blended to produce test materials at four different levels of contamination ranging from 1.0 × 103 to 2.2 × 105 CFU/g. Each material was tested at three different Soleris detection threshold levels determined by the dilution used to inoculate the Soleris vials. Probability of detection analysis was performed to determine if differences in the number of positive results obtained with the two methods were significant.

Results: For all four dried cannabis flower materials, at all three Soleris test thresholds, there were no significant differences in performance comparing the Soleris and reference dilution plating methods as determined by probability of detection analysis at P < 0.05.

Conclusions: It is concluded that the Soleris NF-TVC method is an accurate and effective method for detection of aerobic, mesophilic microorganisms in dried cannabis flower.

Highlights: The Soleris NF-TVC method provides cannabis industry quality control personnel with an effective method for analysis of dried cannabis flower and produces results in 24-48 h.