qPCR, quantitative PCR, Real Time PCR, or rtPCR are not only acceptable methods for microbial enumeration according to the USP, but are superior to traditional culture methods.
The United States Pharmacopeia (USP) does NOT specify any method for microbial enumeration. The USP monograph does refer extensively to Colony Forming Units per gram of sample as a metric, but also discusses its shortcomings and that CFU/g cannot be the only metric. The American Herbal Pharmacopoeia (AHP), another monograph commonly referred to by cannabis regulatory agencies, agrees that CFU/g has limitations.
We at Medicinal Genomics have written extensively about these topics. As industry leaders in cannabis genetics and pathogen safety, our scientists at Medicinal Genomics strongly believe that DNA-based quantitative microbial testing is superior to culture-based plating.
We have published a white paper on the topic as well which we have submitted to the USP and many state regulatory agencies that have requested our input in developing their cannabis safety testing regulations. Please download that paper here: