Foodborne Illness Outbreaks Reported to National Surveillance, United States, 2009-2018

Abstract

Foodborne outbreaks reported to national surveillance systems represent a subset of all outbreaks in the United States; not all outbreaks are detected, investigated, and reported. We described the structural factors and outbreak characteristics of outbreaks reported during 2009-2018. We categorized states (plus DC) as high (highest quintile), middle (middle 3 quintiles), or low (lowest quintile) reporters on the basis of the number of reported outbreaks per 10 million population. Analysis revealed considerable variation across states in the number and types of foodborne outbreaks reported. High-reporting states reported 4 times more outbreaks than low reporters. Low reporters were more likely than high reporters to report larger outbreaks and less likely to implicate a setting or food vehicle; however, we did not observe a significant difference in the types of food vehicles identified. Per capita funding was strongly associated with increased reporting. Investments in public health programming have a measurable effect on outbreak reporting.

Keywords: Salmonella; Shiga toxin–producing Escherichia coli; United States; bacteria; enteric infections; food safety; foodborne diseases; infectious disease outbreaks; norovirus; public health surveillance; viruses.

Figure 1

Mean annual rates of foodborne disease outbreaks reported to the Centers for Disease Control and Prevention per 10 million population by etiology and US state (deidentified), Foodborne Disease Outbreak Surveillance System, United States, 2009–2018. Blue bars represent outbreaks reported for the specified etiology. Gray bars represent all outbreaks reported. Blue and gray bars correspond to the same reporting jurisdiction and are ordered by reporting rate for all single-state outbreaks. A) Norovirus; B) Salmonella; C) bacterial toxins; D) Shiga toxin–producing E. coli O157; E) Other known cause; F) Unknown cause.

Figure 2

Annual rates of foodborne-illness outbreaks per 10 million population by reporting state and etiology, Foodborne Disease Outbreak Surveillance System, United States, 2009–2018. STEC, Shiga toxin–producing Escherichia coli.

Figure 3

Foodborne outbreaks reported through the Foodborne Disease Outbreak Surveillance System, by etiology and reporting group, United States, 2009–2018. A) Single-state foodborne outbreaks by etiology. B) Average outbreaks per state by reporting group (high, middle, low). STEC, Shiga toxin–producing Escherichia coli.

Figure 4

Most common foods implicated in foodborne illness, by detailed food category, Foodborne Disease Outbreak Surveillance System, United States, 2009–2018. Asterisks (*) indicate statistical significance (p<0.05 by Fisher exact test). Data are shown for (A) norovirus, 216 cases; (B) Salmonella, 321 cases; (C) bacterial toxins, 209 cases; D) Shiga toxin–producing Escherichia coli O157, 76 cases; (E) illness of other known etiology, 715 cases; (F) illness of unknown etiology, 191 cases.