P1-125 Title: Validation of RapidChek® E. coli O157 (including H7) and Select™ Salmonella Test Methods for Detection of E. coli O157:H7 and Salmonella species in Cannabis

Monday, August 1, 2016
America's Center - St. Louis
Ann Allen, Romer Labs, Inc., Newark, DE
Meredith Sutzko, Romer Labs, Inc., Newark, DE
Scott Radcliffe, Romer Labs, Inc., Newark, DE
Introduction: Escherichia coli O157:H7 and Salmonella are important human pathogens linked to numerous food borne outbreaks due to the consumption of contaminated raw and processed food products. RapidChek E. coli O157 and SELECT Salmonella test systems can detect these pathogens in cannabis.

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.