Abstract:

Pseudomonas fluorescens (P. fluorescens), Salmonella and Listeria monocytogenes (L. monocytogenes) are 3
species of bacteria that contaminate meat products. The aim of this work was to establish a feasible multiplex polymerase
chain reaction (m-PCR) protocol for simultaneous and rapid detection of these 3 species of bacteria. The specific primers
for the gyrB gene of P. fluorescens, the invA gene of Salmonella and the hlyA gene of L. monocytogenes were designed and
their specificities were determined. In addition, the sensitivities for detecting 3 standard strains and these strains enriched
on meat overnight were tested as well. The results indicated that the m-PCR method had high specificity and sensitivity. For
simultaneous detection of these target microorganisms, the limit of detection (LOD) for pure DNA was 1 pg/μL, and the
LOD for P. fluorescens, Salmonella and L. monocytogenes were 9, 5, and 70 CFU/mL, respectively, by inoculating these 3
strains onto duck meat and overnight culturing at 35 ℃.

Key words: multiplex PCR, detection method, Pseudomonas fluorescens, Salmonella, Listeria monocytogenes