Simultaneous detection by PCR of Escherichia coli, Listeria monocytogenes and Salmonella typhimurium in artificially inoculated wheat grain.
A multiplex PCR procedure was established to detect Escherichia coli, Listeria monocytogenes and Salmonella typhimurium in artificially inoculated wheat grain. The PCR protocol with an enrichment step successfully detected all three organisms inoculated together in non-autoclaved wheat grain. After a one day enrichment, E. coli, L. monocytogenes and S. typhimurium were detected at levels of 56, 1800 and <54 CFU/mL, respectively, in the initial sample. For L. monocytogenes, an improved detection limit of <62 CFU/mL was achieved using singleplex PCR. For autoclaved wheat grain inoculated with the three bacterial strains individually, a detection limit of 3 CFU/mL was achieved after an enrichment step. The ability to test for the three bacteria simultaneously will save time and increase the ability to assure grain quality.
Kim
Jongsoo
J
Canadian Grain Commission, Grain Research Laboratory, Winnipeg, Manitoba, Canada R3C 3G8.
Demeke
Tigst
T
Clear
Randy M
RM
Patrick
Susan K
SK
D000818:Animals; D015169:Colony Count, Microbial / Q000379:methods; D003257:Consumer Product Safety; D004926:Escherichia coli / Q000302:isolation & purification*; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D006801:Humans; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012486:Salmonella typhimurium / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D014908:Triticum / Q000382:microbiology*