Metagenomic analysis of medicinal samples ; Cannabis pathogenic bacteria , toxigenic fungi , and beneficial microbes grow in culture - based yeast and mold tests

The presence of bacteria and fungi in medicinal or recreational Background poses a potential threat to consumers if those microbes include Cannabis pathogenic or toxigenic species. This study evaluated two widely used culture-based platforms for total yeast and mold (TYM) testing marketed by 3M Corporation and Biomérieux, in comparison with a quantitative PCR (qPCR) approach marketed by Medicinal Genomics Corporation. : A set of 15 medicinal samples were analyzed using 3M Methods Cannabis and Biomérieux culture-based platforms and by qPCR to quantify microbial DNA. All samples were then subjected to next-generation sequencing and metagenomics analysis to enumerate the bacteria and fungi present before and after growth on culture-based media. : Several pathogenic or toxigenic bacterial and fungal species were Results identified in proportions of >5% of classified reads on the samples, including Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, Ralstonia pickettii, Salmonella enterica, Stenotrophomonas maltophilia, and Aspergillus ostianus, Aspergillus sydowii, Penicillium citrinum Penicillium Samples subjected to culture showed substantial shifts in the number steckii. and diversity of species present, including the failure of species to Aspergillus grow well on either platform. Substantial growth of and Clostridium botulinum other bacteria were frequently observed on one or both of the culture-based TYM platforms. The presence of plant growth promoting (beneficial) fungal species further influenced the differential growth of species in the microbiome of each sample. : These findings have important implications for the and Conclusions Cannabis food safety testing industries. 1 1 1 1