The Latest Products for Microbial Testing in Cannabis

As cannabis regulations continue to evolve, so do the technologies and products designed to provide definitive results and to safeguard consumers.

The threat of microbial contamination in cannabis is a persistent one. Loosely controlled moisture or humidity during cultivation. Inadequate storage or drying of cuttings. Improper handling and transportation methods.  All of these variables can impact the potential appearance of microbes.

The threat is serious such that each state has instituted specific microbial testing requirements. California for instance, requires the appearance of Salmonella spp. and STEC bacteria to be checked in all cannabis and cannabis products, as well as four types of toxic Aspergillus fungi (A. flavus, A. fumigatus, A. niger, A. terreus) in cannabis products for inhalable consumption.  Colorado adds Staphlococcus aureus, Pseudomonas aeruginosa, and Candida albicans to the list.  Both states specify testing requirements, threshold amounts or permissible limits, for both adult-use recreational and medical cannabis.

As cannabis regulations continue to evolve, so do the technologies and products designed to provide definitive results and to safeguard consumers.  Here are a few recent products and their methods of action in microbial testing applications:

The SPEX CertiPrep Aspergillus qPCR Detection Kit (shown right) allows measurement of the total amount of the four most common strains of Aspergillus: niger, fumigatus, flavus, and terrus.

• Probes for the four strains are labeled with the FAM dye, and the internal control is labeled with HEX/VIC.
• The kits measure the total amount of target and use an internal standard to control for any loss of activity in the reaction master mix.  If the control does not light up, then one or more of the reagents is faulty and the sample will require further analysis.
• This two-color kit does not permit delineation of amounts of the different strains, only total Aspergillus, but it is sensitive down to 10 DNA copies per reactions and it is compatible with most common qPCR systems capable of two-color detection.
• Kits are available at 250, 500, 1000, and 2000 reaction sizes.

Medicinal Genomics offers the PathoSEEK™ line of multi-species Aspergillus detection kits for multiplex qPCR. This includes the Aspergillus 5-Color Multiplex compatible with either CFX96 or AriaMX qPCR devices.

• The 5-plex solution offers improvements over alternative kits which may only quantify individual Aspergillus strains. This saves time and resources when samples fail total mold testing and need to be further scrutinized for individual Aspergillus types. The single PCR reaction means less reagents and instrument usage as well.
• Compatibility with multiple PCR platforms facilitates its use across multiple labs and locations.
• The PathoSEEK 5-Color Aspergillus Multiplex Assay with SenSATIVAx Extraction method has been certified by AOAC International for use in both cannabis flower and cannabis-infused edibles.

Bio-Rad offers the new iQ-Design Assay for rapid real-time PCR detection of microbes in cannabis, food, and environmental samples (shown right).

• This assay is a rapid and complementary addition to the Bio-Rad iQ-Check Real-time qPCR detection kits mentioned previously, which have been validated and certified by AOAC for detection of four pathogenic strains (A. flavus, A. fumigatus, A. niger, and A. terreus) in cannabis flower (10 grams) and both non-solvent- and solvent-based cannabis concentrates (5 grams).
• The iQ-Design includes a positive control to ensure quality of sample prep and reagents, and is compatible with the iQ-Check DNA extraction workflows.
• iQ-Design kits are available for multiplexed testing of three Aspergillus strains in one reaction (A. niger, A. flavus and A. fumigatus) or for individual strain detection in cannabis and cannabis-infused products.

Hardy Diagnostics offers the CompactDry™ plate line for a variety of organism-specific and total count tests.

• These plates incorporate a rigid transparent cassette with removable lid, which provides protection of colonies while allowing easy access for quick inoculation. The gridded back of the cassette facilitates colony counting.
• The plate media is provided within each plate in dry form. Addition of 1 mL of solution turns the media to a gel that diffuses and fills the entire plate. This prevents the need for time sensitive storage of pre-poured plates or the variability that comes with pouring of heated liquid media into empty plates. The dry plates can be stored for extended times at room temperature.
• Another useful feature is the ability to stack plates for increased incubator efficiency without the risk of contamination.
• The CompactDry media is available in eight different formulations for isolation of organisms including: E. coli and Coliforms, Total Yeast and Mold, Staphylococcus aureus, Salmonella, and other stains relevant to cannabis testing and screening.

Hardy Diagnostics also offers the Wizard CompactDry™ Reader, a small automated device for rapid colony counting (shown right).

• The device offers orders of magnitude time savings over manual counting, supporting lab efficiency and high throughput analysis.
• Automated counting equates to increased consistency and precision.
• The Wizard is easy to set up and implement in microbial testing labs.

Check out Hardy Diagnostics listings on LabX

Visit the Cannabis Laboratory application page for further insight and product information.