TABLE 4.
Results of nested PCR performed with spiked food samples with and without enrichment
| Sample | Food sample | No. of Campylo-bacter cells added (CFU/g) | PCR resultsa
|
||||
|---|---|---|---|---|---|---|---|
| Spiked aliquots without enrichment at zero time
|
Spiked aliquots with enrichment on day 1
|
Unspiked aliquot with enrichment on day 1 (100 μl of undiluted broth)
|
|||||
| Analysis of 1 mlb | Analysis of 100 μlb | 100 μl of undiluted brothb | 100 μl of broth diluted 1:10c | ||||
| 1 | Minced beef | 78 | +,+ | +,+ | NDd | ND | − |
| 8 | +,+ | ND | ND | ND | |||
| 0.5 | ND | ND | +,+ | + | |||
| 2 | Minced beef | 130 | +,+ | +,+ | ND | ND | − |
| 13 | +,+ | ND | ND | ND | |||
| 1 | ND | ND | +,+ | + | |||
| 3 | Minced beef | >500 | +,+ | +,+ | ND | ND | − |
| >50 | −,− | ND | ND | ND | |||
| 3 | ND | ND | +,+ | + | |||
| 4 | Minced beef | 120 | +,+ | +,− | ND | ND | − |
| 12 | +,− | ND | ND | ND | |||
| <1 | ND | ND | +,+ | + | |||
| 5 | Chicken | 130 | +,(+)e | +,− | ND | ND | (+) |
| 13 | +,(+) | ND | ND | ND | |||
| 1 | ND | ND | +,+ | + | |||
| 6 | Spiced chicken | 80 | (+),− | +,− | ND | ND | − |
| 8 | −,− | ND | ND | ND | |||
| 0.5 | ND | ND | +,+ | + | |||
| 7 | Pork | 180 | +,− | −,− | ND | ND | − |
| 18 | −,− | ND | ND | ND | |||
| 1 | ND | ND | +,+ | + | |||
a
PCR were performed with 0.25 μM primer during both PCR steps.
b
For each dilution, the results obtained for two parallel aliquots are shown.
c
Enriched broth was diluted 1:10 with sterile Rosef broth prior to PCR.
d
ND, not done.
e
Results in parentheses were difficult to interpret (see text).