Table 4.

Effect of cold stress at 4°C on the enrichment time needed for detection of EHEC in ground beef as assessed by PCR detection of the VT genes

Duration of cold stress (days)Enrichment time (h)EHEC detection with inoculum (CFU/25 g)a of:
22 × 102 × 1022 × 1032 × 1042 × 105
None0NDND++
3+++
6++++
9+++NDNDND
24++NDNDNDND
40NDND
3−/+++
6+++
9+++NDND
24+++NDNDND
80NDNDND
3−/++
6++
9−/+NDND
24++++NDND
  • a ND, not determined; −, negative PCR detection for E. coli strains Co26 and Co7; +, positive PCR detection for E. coli strains Co26 and Co7; −/+, negative PCR detection for E. coli strain Co26, positive PCR detection for E. coli strain Co7.