Fig. 2 Agarose gel electrophoresis demonstrating detection sensitivity of PCR for nontoxigenic E. coli O157:H7 strain 3704 after 6 h primary enrichment
of Glencorse soil. Lanes: (A and L) HyperLadder (Bioline, UK, Ltd); (B) negative control (no template); (C) positive control pure culture DNA;
(D) negative control, uninoculated soil; (E) 1á13 ´ 101
; (F) 1á13 ´ 102
; (G) 1á13 ´ 103
; (H) 1á13 ´ 104
; (I) 1á13 ´ 105
; (J) 1á13 ´ 106
; and (K)
1á13 ´ 107 cfu g±1 soil