MicroSEQ®Listeria spp. Detection Kit

Abstract

Abstract The Applied Biosystems Performance Tested MethodSM for detecting Listeria species in food and environmental samples was compared to the Health Canada reference method (MFHPB-30) for the analysis of five ready-to-eat (RTE) meats (deli turkey, hot dogs, liver paté, deli ham, and raw fermented sausage) and a stainless steel surface. The MicroSEQ method includes the MicroSEQ®Listeria spp. Detection Kit and the option of two different sample preparation kits, either the automated high-throughput PrepSEQ™ Nucleic Acid Extraction Kit or the manual low- to mid-throughput PrepSEQ™ Rapid Spin Sample Preparation Kit. For each sample matrix, 20 replicates were analyzed at two inoculum levels: for RTE meats a low-level inoculum at 0.2–2 CFU/25 g and a high-level inoculum at 2–5 CFU/25 g; and for environmental surfaces, a low-level inoculum at 0.2–2 CFU/5 cm2 sampling area and a high-level inoculum at 2–5 CFU/5 cm2 sampling area. Five control replicates were also analyzed at 0 CFU/25 g (uninoculated) for food or 0 CFU/5 cm2 sampling area for environmental surface. Both sample preparation methods returned identical results. There was no statistically significant difference in the number of positive samples detected by the MicroSEQ Listeria species method and the MFHPB-30 reference method for three RTE meats and for the one stainless steel environmental surface tested. For deli turkey, there was a statistically significant difference in the number of positive results detected by the MicroSEQ method and the Health Canada MFHPB-30 reference method for the low inoculation level, with the MicroSEQ method detecting more positives. For hot dogs, statistical equivalence was not applicable since hot dogs were spiked with 10x Listeria innocua as competitive background, and the MicroSEQ method detects all known Listeria. Because the MicroSEQ method uses real-time PCR to detect pathogens, it provides faster time-to-results with equivalent detection compared to culture methods. The MicroSEQ method detects Listeria species within 2 to 3 h following 24 to 28 h enrichment compared to culture methods that take at least 5 days for presumptive positive results.