AOAC 2019 First Action Methods

AOAC Official Method 2019.10 Listeria species in a Variety of Foods and Select Environmental Samples GENE-UP® Listeria spp. 2 (LIS 2) Test Method First Action 2019

Applicable to detection of Listeria spp. ( monocytogenes, innocua, ivanovii, seeligeri , and welshimeri ) in 25 g test portions of pork rillettes 1 , raw milk 1 , salmon offcuts 1 , mixed precooked vegetables 1 , mixed salad 1 and process water 1 , deli ham 2 , deli turkey 2 , beef hot dogs 2 , breaded chicken nuggets 2 , fresh bagged spinach 3 , fresh bagged lettuce 3 , cooked shrimp 3 , smoked salmon 3 , vanilla ice cream 3 , Mexican soft cheese 3 ; 100 g test portions of whole liquid egg 2 ; 125 g test portions of deli ham 2 and smoked salmon 3 ; 375 g test portions of whey powder 3 ; stainless steel surface sponges 3 .

1 Matrices were validated against ISO 11290-1 Listeria monocytogenes reference method.

2 Matrices were validated against the USDA FSIS MLG Listeria monocytogenes reference method.

3 Matrices were validated against the FDA BAM Listeria monocytogenes reference method.

Caution : Listeria is a Gram-positive, non-spore-forming, aerobic bacillus organism. Care must be taken when handling samples that may contain Listeria spp. Strict compliance with BSL-2 practices, containment equipment, and facilities are recommended for all activities utilizing known or potentially infectious clinical materials or cultures. While BSL-2 containment is suitable for all Listeria , BSL-3 practices and equipment are recommended for activities likely to produce significant aerosols or for activities involving production quantities of this particular organism. Laboratory personnel must be adequately trained to handle pathogens before being permitted to analyze samples for Listeria spp. Follow appropriate safety guidelines when handling potentially contaminated samples. Waste should be disposed of in compliance with local and national legislation. Listeriosis can be life-threatening to certain vulnerable groups, such as pregnant women and those with compromised immune systems and can sometimes be life-threatening to healthy individuals. Pregnant women and immune-compromised individuals should take special care when handling samples that are potentially contaminated with Listeria . See Table 2019.10A for a summary of results of the inter-laboratory study. See table in J. AOAC Int . (future issue) for detailed results of the inter-laboratory study. A. Principle The GENE-UP® Listeria spp. 2 (LIS 2) kit is designed for use with the GENE-UP® Thermocycler. The GENE- UP® LIS 2 kit contains all of the necessary components for PCR, including sample-specific primers and probes and an internal amplification control. The GENE-UP® Thermocycler detects fluorescence at several wavelengths (channels) to allow for multi-target detection in the same reaction vessel. The fluorescent signal from a sample is recorded in channel 640, while the fluorescent signal for an internal amplification control is recorded in channel 705. The software automatically interprets the results for the internal amplification control and determines the sample result based on the outcome of the control. Both the assay for the sample and in the internal amplification control utilize dual Fluorescence