Volume 27, Number 10—October 2021
Synopsis
Novel Outbreak-Associated Food Vehicles, United States
, Preethi Sundararaman, Daniel Dewey-Mattia, Karunya Manikonda, Katherine E. Marshall, Patricia M. Griffin, Brigette L. Gleason, Sanjana Subramhanya, and Samuel J. Crowe
Table 2
Features of outbreaks associated with novel and other food vehicles, United States, 2007–2016*
| Feature | Food vehicle type |
p value† | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Novel |
Other |
|||||||||||
| Outbreaks | Statistic |
Outbreaks | Statistic |
|||||||||
| Mean | Median | Range | Mean | Median | Range | |||||||
| No. cases per outbreak | ||||||||||||
| Primary | 36 | 35.9 | 13.0 | 2–272 | 3,722 | 21.4 | 9.0 | 2–1,939 | 0.04 | |||
| Hospitalized | 32 | 8.2 | 2.0 | 0–70 | 3,502 | 1.6 | 0.0 | 0–308 | <0.001 | |||
| Died |
34 |
0.4 |
0.0 |
0–7 |
3,520 |
0 |
0.0 |
0–33 |
<0.001 |
|||
| % Cases per outbreak | ||||||||||||
| Hospitalized | 32 | 25.4 | 16.9 | 0–100 | 3,502 | 9.9 | 0.0 | 0–100 | <0.001 | |||
| Died |
34 |
2.9 |
0.0 |
0–50 |
3,520 |
0.4 |
0.0 |
0–100 |
<0.001 |
|||
| Outbreaks, no. (%) | ||||||||||||
| Multistate | 36 (61.1) | 3,722 (5.7) | <0.001 | |||||||||
| Had recall | 35 (48.6) | 3,567 (5.2) | <0.001 | |||||||||
| Etiology Salmonella‡ | 34 (55.9) | 2,226 (28.3) | <0.001 | |||||||||
*Data from Centers for Disease Control and Prevention Foodborne Disease Outbreak Surveillance System, 2007–2016. Analysis limited to outbreaks with an implicated food. This analysis included outbreaks resulting from a range of contributing factors, including contamination from ill food workers (and not resulting from more upstream processes). None of the outbreaks associated with a novel food vehicle were linked to an ill food worker. As a sensitivity analysis, 584 outbreaks linked to ill food workers were excluded from the comparison group, leaving 3,138 outbreaks. Among these, the median number of primary cases was 8.0; hospitalizations, percent of cases hospitalized, and deaths, and percent of cases resulting in death were all 0; 6.8% of outbreaks were multistate, 6.1% had a recall, and 31.6% had an etiology of Salmonella. All statistical results remained robust with p<0.05. †Nonparametric Wilcoxon testing was used to assess statistical difference in means. χ2 testing was used to assess statistical differences in percentages. ‡Limited to single-etiology outbreaks that met confirmation guidelines. Outbreaks associated with a novel food vehicle were more likely to be caused by Salmonella contamination. These outbreaks are more likely to result in large, multistate outbreaks leading to public health investigations. As a sensitivity analysis, we restricted the sample to outbreaks with an etiologic agent of Salmonella leaving 649 outbreaks (19 linked to novel food vehicles and 630 linked to other outbreaks). Case effects did not remain significant (i.e., when comparing novel and other outbreaks, we found no statistically significant differences in primary cases, hospitalization, deaths, as well as percent of cases hospitalized and percent of cases resulting in death). However, outbreaks associated with a novel food were more likely than other outbreaks to have cases exposed in multiple states (84.2% for novel and 17.8% for other outbreaks, p<0.001) and result in a recall (63.2% for novel and 8.9% for other outbreaks, p<0.001).