An 8-hour system for Salmonella detection with immunomagnetic separation and homogeneous time-resolved fluorescence PCR

• Published in: International journal of food microbiology Vol. 125; no. 2; pp. 158 - 161
• Main Authors: Hagren, Virve, von Lode, Piia, Syrjälä, Anniina, Korpimäki, Teemu, Tuomola, Mika, Kauko, Otto, Nurmi, Jussi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.07.2008; [Amsterdam; New York, NY]: Elsevier Science; Elsevier
• Subjects: analytical methods; Automation; bacterial contamination; Biological and medical sciences; Dry chemistry; enrichment culture; Fluorescence; Fluorometry - methods; Fluorometry - standards; food contamination; Food Contamination - analysis; Food industries; food matrix; Food microbiology; food pathogens; Fundamental and applied biological sciences. Psychology; Gene Amplification; General aspects; Homogeneous assay; Immunomagnetic separation; Immunomagnetic Separation - methods; Immunomagnetic Separation - standards; isolation; Methods of analysis, processing and quality control, regulation, standards; microbial detection; PCR; polymerase chain reaction; Polymerase Chain Reaction - instrumentation; Polymerase Chain Reaction - methods; Polymerase Chain Reaction - standards; rapid methods; Salmonella; Salmonella - classification; Salmonella - immunology; Salmonella - isolation & purification; Sensitivity and Specificity; Species Specificity; Time Factors; Time-resolved fluorometry; Salmonella; Immunomagnetic separation; Time-resolved fluorometry; Homogeneous assay; Dry chemistry; PCR; Polymerase chain reaction; Analysis method; Separation; Salmonella,Immunomagnetic separation,Homogeneous assay,PCR,Time-resolved fluorometry,Dry chemistry; Fluorescence; Bacteria; Control method; Molecular biology; Detection; Fluorescence spectrometry; Enterobacteriaceae
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2008.03.037

We describe a system consisting of rapid sample enrichment and homogeneous end-point PCR analysis that enables the detection of Salmonella in various food matrices in 8 h. Sample preparation starts with 6 h enrichment step in supplemented broth, after which Salmonella cells are collected with immunomagnetic particles. The particles are washed and dispensed to ready-to-use PCR reaction vessels, which contain dried assay-specific reagents and an internal amplification control. PCR is performed with a novel instrument platform utilising the sensitive label technology of time-resolved fluorometry. Qualitative assay results are automatically interpreted and available in 45 min after sample addition. The overall accuracy, sensitivity and specificity of the Magda™ CA Salmonella system were 99.1%, 98.4% and 100.0%, respectively, based on the evaluation of 107 samples (beef, pork, poultry and ready-to-eat meals) artificially contaminated with sub-lethally injured Salmonella cells.