On August 18th, 2022 MGC released a new PathoSEEK® Bile Tolerant Gram Negative (BTGN) bacteria detection assay and updated workflow. This includes a new User Guide and a new Validation document. Here's what changed.
- Affects both flower samples and marijuana infused products (MIPs)
- Note: There will no longer be a Cq to CFU conversion for MIP samples provided by MGC. Due to the low action limit of 100 CFU/g in most jurisdictions, we recommend enriching non flower samples in TSB and processing as pass/fail. This process is described in the updated BTGN v2 user guide and will ensure viable BTGN bacteria is detected if present. If BTGN is detected post enrichment, plating should be performed to achieve a total viable count for reporting of CFUs. If no BTGN is detected in a sample extracted after enrichment then this sample can be reported as not detected.
- Requires PathoSEEK Master Kit v3 (SKU 420201) for both flower samples and marijuana infused products (MIPs)
- Changes the initial, upfront dilution to 19mL of Tryptic Soy Broth per 1g of sample for flower samples
- Adds a centrifugation step to pellet cells prior to lysis (flower only)
- Requires new product SKUs:
- PathoSEEK Bile-Tolerant Gram-Negative Bacteria Detection Assay v2 (SKU 420149)
- Reduced concentrations of SCCG internal control and pseudomonas primers are only differences with v2
- PathoSEEK Bile-Tolerant Gram-Negative / Coliform / Entero Multiplex Positive Control (SKU 420353)
- This new positive control can be used with our BTGN v2 assay as well as the forthcoming Coliform & Entero assay
- PathoSEEK Bile-Tolerant Gram-Negative Bacteria Detection Assay v2 (SKU 420149)
- Adds a back-calculation to the recommended Cq to CFU/g conversion equation to account for the revised upfront dilution (only applies to flower matrix)
PathoSEEK® Bile Tolerant Gram Negative Detection Assay v2 Validation Data
We have removed Bile Tolerant Gram Negative Version 1 SKU from our menu. If you have not yet upgraded your documentation or validation, you can use the Version 2 assay in place of the Version 1 assay without issue - if still using the original protocol. When compared with Version 2 using the original protocol there is zero curve shift. The only difference is a slightly lower concentration of the SCCG internal control ( the primers and probe that target cannabis DNA). When compared with Version 2 using the original protocol there is zero curve shift. The primers and probe that target BTGN have not changed.