Table 1.
Case-case comparison of cheeses and selected other food exposure frequencies in outbreak-related cases and sporadic cases of listeriosis reported to the Listeria Initiative*
| Food frequency, n/N (%) |
|||||||
|---|---|---|---|---|---|---|---|
| Food exposure | Outbreak-related cases (N = 10) | Sporadic cases (N = 204) | mOR | (95% CI) | P value | ||
| Any soft cheese† | 9/10 | (90) | 51/138 | (37) | 17·3 | (2·0–825·7) | 0·003 |
| Brie | 4/9 | (67) | 14/134 | (10) | 5·7 | (1·0–31·7) | 0·04 |
| Feta | 5/9 | (56) | 22/134 | (16) | 8·9 | (1·4–96·6) | 0·02 |
| Blue or Gorgonzola | 5/9 | (56) | 16/134 | (12) | 4·9 | (0·8–29·2) | 0·09 |
| Camembert | 3/9 | (33) | 2/133 | (2) | 26·4 | (1·6–1921·7) | 0·02 |
| Goat’s cheese | 2/9 | (22) | 11/136 | (8) | 3·9 | (0·3–31) | 0·33 |
| Mexican-style cheese | 1/10 | (10) | 24/135 | (18) | 0·4 | (0·01–4·0) | 0·76 |
| Farmer’s cheese | 0/10 | (0) | 2/137 | (1) | 17·3 | (0–145·0‡) | 1·0 |
| Other soft cheese | 7/10 | (70) | 20/136 | (15) | 17·2 | (2·9–182·4) | 0·0006 |
| Yogurt | 8/10 | (80) | 52/129 | (40) | 11·9 | (1·4–563·4) | 0·01 |
| Turkey delicatessen meat | 4/10 | (40) | 52/138 | (38) | 1·0 | (0·2–4·8) | 1·0 |
| Pâté | 2/10 | (20) | 5/134 | (4) | 3·6 | (0·2–34·3) | 0·43 |
Sporadic cases (i.e. cases not associated with any recognized cluster or outbreak) reported to the Listeria Initiative from 2008 to 2012 in patients residing in counties with a grocery chain A store were included (see text). Matched odds ratios (mORs), 95% confidence intervals (CIs), and two-tailed P values were estimated using exact conditional logistic regression adjusting for patient state of residence.
Any soft cheese was an aggregate variable, which included exposure to the following cheeses: blue or Gorgonzola, Brie, Camembert, farmer’s, feta, goat’s, and other soft cheese. Mexican-style cheese (queso fresco) was excluded.
Median unbiased estimate.