Evaluation of PMA-qPCR methodology to detect and quantify viable Shiga toxin-producing Escherichia coli in beef burgers M

REY, MARÍA DE LOS ÁNGELES; RODRÍGUEZ RACCA, ANABEL; MARINA VALERIA MOZGOVOJ; CAP, MARIANA; DUS SANTOS MARIA JOSE; FAVRE, LEONARDO CRISTIAN; VAUDAGNA, SERGIO R.

JOURNAL OF FOOD PROCESSING AND PRESERVATION

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021

0145-8892

AbstractPropidium monoazide (PMA) is a selective nucleic acid intercalating dye that can becombined with real-time PCR (qPCR) in order to evaluate cell viability in food samples. The aim of the present work was to evaluate PMA-qPCR to detect and quantifyviable STEC cells in beef burgers using stx2 as target gene. First, it was determinedthat 100 µM of PMA could inhibit qPCR signal from non-viable cells and had no influence on the amplification of different concentrations of viable cells. Then, it wasshown that PMA efficiently distinguished between different log cfu of viable cellsin presence of a high concentration of non-viable cells, both in culture and in beefburger homogenates. Finally, it was determined that PMA could distinguish betweenviable and non-viable cells within the same log cfu in beef burger homogenates.PMA-qPCR effectively detected and quantified viable STEC cells in culture and inbeef burger homogenates.Novelty impact statement: The main achievement of this work is that we demonstrate PMA-qPCR could not only detect, but also quantify viable STEC cellstargeting stx2 gene, even in the presence of a high concentration of non-viableSTEC cells in a complex matrix as beef burgers. This methodology can be used toassess effectiveness of antimicrobial treatments to reduce STEC contamination inmeat products more rapidly and with less pathogenic residues than conventionalmethods.