A University of California Davis study discovered bacteria and mold on medical cannabis samples from 20 Northern California dispensaries, according to a Sacramento Bee report. The study results were published in the journal of Clinical Microbiology and Infection.
Dr. George Thompson, UC Davis Department of Microbiology and Immunology, warned against patients with weakened immune systems from smoking, vaping or inhaling aerosolized cannabis, but indicated “for the vast majority of cannabis users, this is not of great concern.” He said that those with weakened immune systems are advised to avoid unwashed produce and cut flowers because they might contain potentially harmful mold, bacteria, and fungi and believes cannabis should be added to that list.
“…It’s a big oversight in our opinion,” Thompson said in the report. “It’s basically, dead vegetative material and always covered in fungi.”
The study was conducted after two UC Davis patients died from lung infections believed to be caused by tainted cannabis, however that cannot be confirmed without samples of the products they were using before they fell ill. Dr. Joseph Tuscano, a cancer specialist at UC Davis, called for the study after several leukemia and lymphoma cancer patients developed rare, severe lung infections.
The cannabis was tested by Steep Hill Laboratories in Berkeley and all of the samples reportedly tested positive for bacteria and fungi, some related to severe lung infections.
Thompson said that cannabis edibles might be an alternative to smoking or vaping cannabis for those at risk.
“I give that advice with a caveat: We don’t know it’s safer, we think it probably is,” he said.