Molecular methods are being increasingly applied to detect, quantify and study microbial populations in
food or during food processes. Among these methods, PCR-based techniques have been the subject of
considerable focus and ISO guidelines have been established for the detection of food-borne pathogens.
More particularly, real-time quantitative PCR (qPCR) is considered as a method of choice for the detection
and quantification of microorganisms. One of its major advantages is to be faster than conventional
culture-based methods. It is also highly sensitive, specific and enables simultaneous detection of
different microorganisms. Application of reverse-transcription-qPCR (RT-qPCR) to study population
dynamics and activities through quantification of gene expression in food, by contrast with the use of
qPCR, is just beginning. Provided that appropriate controls are included in the analyses, qPCR and
RT-qPCR appear to be highly accurate and reliable for quantification of genes and gene expression. This
review addresses some important technical aspects to be considered when using these techniques.
Recent applications of qPCR and RT-qPCR in food microbiology are given. Some interesting applications
such as risk analysis or studying the influence of industrial processes on gene expression and microbial
activity are reported.
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