PCR-based methodologies for detection and characterization of Listeria monocytogenes and Listeria ivanovii in foods and environmental sources

Listeria monocytogenes is an important foodborne pathogen responsible for listeriosis, a fatal disease. It is widely distributed in various foods and environmental sources. In this review, we focused on addressing PCR-based technologies, including conventional PCR, qPCR and droplet digital PCR (ddPCR). Specifically, we described (a) conventional PCR and mono-, duplex- and multiplex-qPCR methodologies; (b) development and applications of gene HlyA-, Iap-, PrfA - and SsrA-based conventional and qPCR assays as well as PCR assays targeting newly identified gene targets for specific detection of L. monocytogenes; differentiation of viable from dead L. monocytogenes by qPCR in conjugation with propidium monoazide pretreatment; PCR-based serotype identification of L. monocytogenes isolates; PCR-based detection of L. ivanovii, infecting ruminants, differentiation of L. monocytogenes from other Listeria species; and sigB-gene based PCR identification of Listeria spp; (c) applications of ddPCR in detection of L. monocytogenes; and (d) application of qPCR assays in detection and subtyping of L. monocytogenes in milk and dairy products; meats, meat products and meat-processing environment; and seafood, seafood products and processing environment. Our goal was to provide a relatively comprehensive overview of PCR-based methodologies available in detection, characterization and subtyping of various strains of L. monocytogenes in foods and environmental sources.