Purpose: The aim of these studies was to evaluate the performance of the E. coli and Salmonella test systems for the detection of E. coli O157:H7 and Salmonella spp. in cannabis.
Methods: For each study, Cannabis samples (1g) were inoculated with a low-level (3.0 cells per sample) inoculum of E. coli ATCC 35150 or with a low level (1.7 cells per sample) inoculum of Salmonella Typhimurium ATCC 14028. Twenty-two (22) samples, 20 low-level inoculated and 2 non-inoculated samples, were analyzed by each method.
Samples for the E. coli O157 test method were enriched in 9 mL of enrichment media and evaluated and screened with test strips at a total time of only 8 hours, and confirmed by using CT-SMAC agar, while samples for the Salmonella test method were enriched in 9 mL of primary media, transferred to secondary media, and evaluated with test strips at a total time of just 22 hours and confirmed using XLD agar.
Results: Both test method detected 20 out of 20 low-level inoculated cannabis samples. The negative controls were reported as negative with both methods. All presumptive test results confirmed via cultural confirmation on either CT-SMAC agar for E. coli O157 or XLD agar for Salmonella. Both methods exhibited 100% sensitivity and 100% specificity in these studies.
Significance: The E. coli test system detects low levels of E. coli O157 species in cannabis in as little as 8 hours and the Salmonella test system detects low levels of Salmonella spp. in cannabis in as little as 22-30 hours. RapidChek will provide method users with rapid, reliable, cost effective tools for monitoring and controlling E. coli O157 and Salmonella species in cannabis.