Use 19 mL TSB/1 g cannabis for the detection of bacterial targets like Salmonella and Shiga-Toxin Producing E. coli.
The PathoSEEK® with SenSATIVAx® methods for the detection of Salmonella and STEC in cannabis flower were developed using a 1:10 ratio of cannabis:TSB. However, enumeration tests using PathoSEEK® with SenSATIVAx® require a 1:20 dilution, resulting in the need for two separate test portions. To streamline this process end users may wish to first assess a sample using a PathoSEEK® enumeration method, then enrich the remaining sample for the detection of Salmonella and E. coli or other bacterial targets.
This method modification is not covered by any accredited claims and we recommend performing a verification experiment to document the applicability of the modification in your lab:
Choose an organism from the inclusivity list for the assay of choice and streak to a single colony on appropriate agar media.
Isolate a single bacterial colony using a pipette tip or sterile toothpick and inoculate 19 ml of TSB in a Whirl-Pak bag containing 1 g of cannabis matrix. Repeat using 1 g of cannabis matrix and 9 mL TSB. Homogenize the inoculated samples by hand for one minute then remove and discard 1 mL of inoculated sample from the sample bag containing 19 ml TSB.
Hand homogenize the sample bags for one minute and enrich for 16 hours at 37°C.
After enrichment, hand homogenize the sample bags for one minute and perform SenSATIVAx® DNA Purification followed by qPCR using the appropriate PathoSEEK® detection assay.
Data below show results of the experiment with Salmonella:
