Detection of Escherichia coli O157:H7 in raw meat by immunomagnetic separation and multiplex PCR.
The aim of this research was to elaborate fast and sensitive method ofdetection of E. coli O157:H7 in food samples. Raw ground meat obtained from retail was artificially inoculated with low numbers of E. coli O157:H7. 18 h enrichment culture allowed pathogenic bacteria to multiply to the levels detectable in multiplex PCR. Immunomagnetic separation with magnetic beads coated with an antibody against E. coli O157:H7 were used to concentrate target bacteria and to separate PCR inhibitors. A portion of the bacterial suspension was used in a multiplex PCR to amplify eae (attaching and effacing) gene, stx (shiga toxin) genes and 90 kbp plasmid. The sensitivity of E. coli O157:H7 detection method was shown to be 1 cfu per 25 g of food sample. The total analysis can be completed within 24 h, whilst traditional methods involves enrichment, direct plating and confirmation tests with entire time at least 3 days.
Lekowska-Kochaniak
Aneta
A
Department of Microbiology, National Food and Nutrition Institute, Powsińska 61/63, 02-903 Warsaw, Poland.
Czajkowska
Danuta
D
Popowski
Janusz
J
D000818:Animals; D002417:Cattle; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D018189:Immunomagnetic Separation / Q000379:methods*; D008460:Meat / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity