TABLE 2.
Number of food samples that contained different concentrations of L. monocytogenes separated by inlA subgroups
| Concn interval (log CFU/g) | No. of samples by subtype |
|||
|---|---|---|---|---|
| inlA without PMSC | inlA with PMSC | inlA with PMSC4 | All positive samplesa | |
| −2-−1 | 188 | 146 | 18 | 398 |
| −1-0 | 38 | 38 | 4 | 81 |
| 0-1 | 25 | 26 | 6 | 53 |
| 1-2 | 13 | 7 | 1 | 20 |
| 2-3 | 10 | 6 | 2 | 16 |
| 3-4 | 1 | 2 | 0 | 3 |
| 4-5 | 0 | 0 | 0 | 0 |
| 5-6 | 0 | 2 | 2 | 2 |
| Avg doseb (CFU/serving) | 1.76 × 103 | 2.00 × 105 | 1.36 × 106 | 8.03 × 104 |
a
The data for all the positive samples from the RTE food survey reported by Gombas et al. (12) are included for comparison. There were a total of 573 L. monocytogenes-positive samples among the 31,707 food samples tested; isolates from 502 samples were obtained and subjected to inlA subtyping.
b
The average dose per serving, given detection of L. monocytogenes in the RTE food survey, was determined from the discrete frequency data for each subgroup by using the mid-bin value for each interval and Weibull (1.40, 76.60) + 1.18 as the distribution for serving size.