Table 2.
PNA-FISH results obtained for the detection of E. coli O157:H7 on different food matrices inoculated with concentrations between 0.01 and 100 CFU per 25 g or mlc
| Concn (CFU/25 g or ml) | PNA-FISH result (PP/TPa) for: |
|||||
|---|---|---|---|---|---|---|
| Ground beef |
Unpasteurized milk | |||||
| 37°C |
41.5°C |
|||||
| mTSB+Nb | BPW | mTBS+N | BPW | 37°CmTBS+Nb | 41.5°CmTBS+N | |
| 100 | + (6/6) | + (6/6) | + (6/6) | + (6/6) | + (6/6) | + (6/6) |
| 10 | + (6/6) | + (4/6) | + (6/6) | + (2/6) | +(6/6) | + (6/6) |
| 1 | + (5/6) | − (0/6) | + (5/6) | − (0/6) | + (6/6) | + (6/6) |
| 0.1 | − (0/0) | − (0/0) | − (0/0) | − (0/0) | − (0/0) | − (0/0) |
| 0.01 | − (0/0) | − (0/0) | − (0/0) | − (0/0) | − (0/0) | − (0/0) |
a
PP/TP, number of samples that tested positive by PNA-FISH/total number of positive samples as determined by the culture method.
b
Results were considered for the determination of the method sensitivity, specificity, and accuracy.
c
Results for the three independent assays, performed for two E. coli O157:H7 strains, are provided.