Reverse-Transcriptase Loop-Mediated Isothermal Amplification as a Rapid Screening/Monitoring Tool for Salmonella Enterica Detection in Liquid Whole Eggs
Article first published online: 21 FEB 2012
© 2012 Institute of Food Technologists®
Journal of Food Science
Volume 77, Issue 4, pages M200–M205, April 2012
How to Cite
Techathuvanan, C. and D'Souza, D. H. (2012), Reverse-Transcriptase Loop-Mediated Isothermal Amplification as a Rapid Screening/Monitoring Tool for Salmonella Enterica Detection in Liquid Whole Eggs. Journal of Food Science, 77: M200–M205. doi: 10.1111/j.1750-3841.2011.02601.x
- Issue published online: 19 APR 2012
- Article first published online: 21 FEB 2012
- MS 20111050 Submitted 8/31/2011, Accepted 12/12/2011.
- loop-mediated isothermal amplification;
- Salmonella enterica
Abstract: 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 invA primers. After 16 and 12-h enrichment, improved Salmonella detection up to 100 to 101 and104 CFU/25 mL LWE, respectively was obtained. Without enrichment, Salmonella could be detected at 107 CFU/25 mL; however, after 6-h enrichment a 1-log improvement to 106 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.