The challenge to quantify Listeria monocytogenes– a model leading to new aspects in molecular biological food pathogen detection


Martin Wagner, Institute of Milk Hygiene, Milk Technology and Food Science, Department of Veterinary Public Health and Food Science, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria. E-mail:


In this work, we discuss the latest insights concerning advantages and disadvantages and the nature of microbiological and molecular methods for quantitative food pathogen detection. The assessment of molecular methods must be brought on a basis that considers the nature of molecular methods and their underlying mechanism. A potential approach to setting up the development, validation and structure of an analytical chain is presented based on quantitative real-time PCR (qPCR). This is analysed exemplary on the basis of recent work using the model organism Listeria monocytogenes. Several prerequisites for successful quantitative detection of this pathogen will be discussed. In particular, sample preparation, controls for all methodical steps and the validation of the core assay qPCR are addressed, which constitute the basis for a reliable analytical detection chain for molecular biological pathogen detection from food. Microbiological methods are analysed based on growth of the single cell, which is the fundament of these traditional methods.