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Evaluation of The Maldi-tof-ms For The Detection of Listeria Monocytogenes in Ready-to-eat Food Products


Project TitleEvaluation of the Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry(MALDI-TOF-MS) for the detection of Listeria monocytogenes in Ready-To-Eat Imported Food ProductsAbstractAim: This proposal will evaluate the use of the MALDI-TOF-MS system to detect L. monocytogenes inhigh-risk foods (HRFs) such as Ready-to-Eat (RTE) imported foods that may be eaten uncooked (e.g.,preserved fish, deli meats) or re-heated ( e.g. frankfurters) or eaten raw ( fruits, vegetables like sprouts).L. monocytogenes has the ability to grow in cold storage or refrigerator temperature where RTE foodproducts, imported or locally made (cheese, deli meats, preserved fish, cooked-ready-to-eatcrustaceans, etc.) are stored. (3)Method: MALDI-TOF-MS technology will be used to identify L. monocytogenes directly from a selectiveenrichment broth that has been incubated for 30 hours to allow the organism to grow and multiplyin numbers that can be detected without culture and isolation on a plated media. We willdemonstrate that the MALDI-TOF-MS system identifies L. monocytogenes through laser desorptionionization of the sample attached to a matrix crystals. This process generates a unique mass spectralpattern or fingerprint that can be used to compare with reference libraries in the MALDI-TOF-MS systemdatabase to identify the microorganism. (4) (5) (6)Significance and Impact of the Study: It is critical to have a rapid method to detect L. monocytogenesbecause of its ability to grow in cold storage or refrigerator temperature where RTE food products,imported or locally made are stored. (3) The HRF designation of RTE foods is based on several factorsas defined in Section 204 (d) (2) (A) of the Food Safety Modernization ACT (FSMA). (1) Rapiddetection of L. monocytogenes from contaminated RTE imported foods is critical in preventing thedistribution of RTE food/food products contaminated with L. monocytogenes that continues tocontinuous to proliferate/multi[ply while in storage.

Whelen, Andrew C
Hawaii State Department of Health
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