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Reverse‐Transcriptase Loop‐Mediated Isothermal Amplification as a Rapid Screening/Monitoring Tool for Salmonella Enterica Detection in Liquid Whole Eggs
Author(s) -
Techathuvanan Chayapa,
D'Souza Doris Helen
Publication year - 2012
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2011.02601.x
Subject(s) - loop mediated isothermal amplification , salmonella , salmonella enterica , tetrathionate , reverse transcriptase , chromatography , chemistry , microbiology and biotechnology , agar , serial dilution , biology , polymerase chain reaction , dna , bacteria , biochemistry , medicine , alternative medicine , pathology , gene , genetics
Reverse‐transcriptase loop‐mediated isothermal amplification (RT‐LAMP) is a novel molecular detection method that is specific, fast, and simple. It is based on reverse transcription followed by DNA amplification using the Bst DNA polymerase large fragment requiring one temperature and a simple waterbath, without the need for any expensive equipment. Detection is by turbidity or agarose gel electrophoresis. Our objective was to apply this LAMP‐based technology to rapidly and sensitively detect Salmonella enterica serovar Enteritidis in liquid whole eggs (LWEs) within 1 d. LWE were inoculated with S . Enteritidis and stomached in tetrathionate broth (TTB), and spread‐plated on Xylose lysine tergitol 4 agar either immediately or after 6, 12, or 16‐h enrichment. RNA was extracted from 5‐mL TTB and the RT‐LAMP assay was carried out using inv A primers. After 16 and 12‐h enrichment, improved Salmonella detection up to 10 0 to 10 1 and10 4 CFU/25 mL LWE, respectively was obtained. Without enrichment, Salmonella could be detected at 10 7 CFU/25 mL; however, after 6‐h enrichment a 1‐log improvement to 10 6 CFU/25 mL was obtained. This RT‐LAMP assay appears to be suitable as a potential screening/monitoring tool for Salmonella enterica from LWE products in routine settings with results obtainable within 24‐h, which is significantly faster than traditional cultural assays.