Microbial Impurity Testing

The same conditions that are ideal for the cultivation of cannabis can also be ideal for the proliferation of microorganisms such as bacteria, fungi, and yeast. If cannabis and cannabis products are not properly screened, they can be contaminated with a variety of harmful pathogens. Ingesting these contaminants can lead to serious illness, health complications, or accelerated degradation of the material. To address this issue, SC Labs offers 2 microbial impurity testing options.


Real-Time Quantitative Polymerase Chain Reaction (qPCR)

Identifying microorganisms that are harmful versus harmless holds great value for those in our industry. SC Labs is able to accomplish this through quantitative polymerase chain reaction (qPCR) technology—the future of DNA-based testing methods and screening for microbial impurities.

qPCR’s high sensitivity can detect and identify specific species of contaminants by utilizing the natural mechanisms of genetic amplification and engineered fluorescent probes. DNA probes are designed to bind to the 16s RNA region which is unique to particular species. When this binding occurs, a fluorescent molecule is cleaved from the probe, and the fluorescence is detected with calibrated instrumentation. The intensity of fluorescence, measured in refractory units (RFU), is captured by the instrumentation and displayed on an x,y graph.

SC Labs prides itself on providing reliable results, and our qPCR assay has been successfully validated against performance requirements set forth by the Bureau of Cannabis Control (BCC)1 and the US Food and Drug Administration (FDA)2.

  1. Bureau of Cannabis Control, Title 16 California Code of Regulations, § 5713 Validation of Test Methods for microbial analysis of samples
  2. US Food and Drug Administration Guidelines for the Validation of Analytical Methods for the Detection of Microbial Pathogens in Foods and Feeds, 2nd Edition, April 2015, Single Laboratory Validation for a Qualitative Detection Emergency Use method guidelines for the detection of Shiga-toxin producing E. coli (STEC), Salmonella species, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger and Aspergillus terreus.

3M Petrifilm

Petrifilms are designed to detect and enumerate various micro-organisms quickly and efficiently. They have a ready-made culture medium that contains a cold-water-soluble gelling agent, nutrients, indicator dye, and a built-in grid to provide contrast facilitate the counting of colony forming units (CFU). Plating is a quality indicator for overall microbial load, and it cannot always discern harmful pathogens from beneficial or benign organisms. Species specificity is available for E. coli and Salmonella, while other colonies can be isolated and identified using qPCR.

3M Petrifilm plates are ISO 9002 certified for design and manufacturing, and they are included in the official methods of analysis of AOAC International. They are also recognized in the United States by the American Public Health Association; the USDA Agricultural Marketing, Food Safety and Inspection Service; and the US Food and Drug Administration.

SC Labs readily offers plating services with the following 3M Petrifilm products: Rapid Yeast and Mold Count Plates, E. coli/Coliform Count Plates and Aerobic Count Plates. We can also provide plating services with other 3M Petrifilm products, such as Enterobacteriaceae, Environmental Listeria, among others.

microbial impurity testing through petrifilm and plating

Environmental Swabs

Contaminants are everywhere, and ensuring prep surfaces and equipment don’t act as a transmission agent is an ongoing effort. Swabbing not only provides peace of mind before investing production resources, it pin-points high-risk areas and sources of contamination.

Environmental swabs are a tool that facilities use to screen and identify sources of contamination. A variety of different surfaces can be swabbed–table tops, vents, ventilation systems, fans, manufacturing equipment, etc. Each individual swab is in a self-contained tube that can be reliably resealed. The swabs are pre-moistened with a neutralizing buffer to ensure microbial organisms maintain viability during transport.

SC Labs can provide assistance with instructions on how to map, track, and swab facilities. Testing of the swabs for microbial impurities can be performed through qPCR or plating.

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