Real-Time Quantitative PCR as a Tool for Monitoring Microbiological Quality of Food

Abstract

Microbiological parameters of food provide quality information regarding the processing, storage, and distribution conditions, shelf life, as well as whether the food poses a health risk to the population. In this context, the concern with food safety is a competitive advantage, as the pressure of consumers, who are increasingly interested and concerned about what they are consuming, directs the trade to reach the quality of products and services offered. With regard to microbiological analyses, researchers have been developing sensitive techniques to produce rapid results, since traditional methods of microbiological culture are time-consuming and very laborious. Thus, the real-time quantitative PCR technique (qPCR) offers the possibility of quantifying the total bacterial DNA in a food sample without the need of the microbial growth step. That is, the result can be expressed on the same day, and it is possible to perform a simultaneous quantification of more than one pathogen in a single assay. Therefore, it can be a useful tool for monitoring microbiological quality in food industries. In this chapter, we will present the advantages and disadvantages of this methodology for food microbiology emphasizing the challenge of differentiating viable cells from nonviable cells.

A comparison of <i>Listeria monocytogenes</i> growth monitoring in ground pork samples by real-time polymerase chain reaction to conventional agar and most probable number methods

“…Real-time PCR has been recognized as a powerful tool for quantitative bacterial detection from food materials that is highly sensitive and specific (Kimura et al, 2001;Rodríguez-Lázaro et al, 2004;Mafu et al, 2009;Liu et al, 2019). Several studies have compared the application of real-time PCR to plate counting, optical density, and other methods (Reichert-Schwillinsky et al, 2009;Macé et al, 2013;Ilha et al, 2016;Ricchi et al, 2017;Lopes and Maciel, 2019). However, no study has utilized real-time PCR quantification to generate bacterial growth data from food materials for the construction of growth prediction models in comparison with other methods.…”

Absolute quantification of E. coli virulence and housekeeping genes to determine pathogen loads in enumerated environmental samples

“…First, you create a standard curve; then you compare unknowns to the standard curve and extrapolate a value. It relies on an internal or external calibration curve, and these standard curves are used to derive the input template copy number and to ensure that the exact transcript copy number is determined [ 15 , 17 ]. Absolute quantitative methods have been found to be more sensitive to gene expression variations caused by factors such as developmental and environmental variation [ 18 , 19 ].…”