QUANTITATIVE DETECTION OF ESCHERICHIA COLI O157:H7 IN GROUND BEEF BY IMMUNOMAGNETIC SEPARATION AND POLYMERASE CHAIN REACTION

摘要: ABSTRACT A quantitative assay for viable Escherichia coli O157:H7 in ground beef based on immunomagnetic separation (IMS) and the polymerase chain reaction (PCR) was developed. Bacterial cells inoculated into beef, were captured by beads (IMB) after a 6 h non-selective enrichment. The percent capture of target consistent inoculation levels 0.7 to 70 colony-forming-units (CFU)/g. Captured bacteria lysed with PCR buffer containing 0.2 mg/mL proteinase K at 65°C 30 min. DNA sequences Shiga-like toxin 1 2 (Stx 2) amplified independently. Log-linear relationships observed between CFU E. integrated fluorescent image products Stx primers range CFU/g.