Trends in Foodborne Illness in the United States,
Documenting trends in foodborne illness—which illnesses are decreasing and which are increasing—is essential to the overall goal of reducing foodborne illness. FoodNet has been tracking trends in the most common infections transmitted through food since 1996.
Each year, FoodNet reports on the changes in the number of people in the United States sickened with foodborne infections that have been confirmed by laboratory tests. This annual report card also lets CDC, its partners, and policy makers know how much progress has made in reaching national goals for reducing foodborne illness.
Figure 1. Relative rates of laboratory-confirmed infections with Campylobacter, E. coli O157*, Listeria, Salmonella, and Vibrio, compared with 1996--1998 rates, by year --- Foodborne Diseases Active Surveillance Network, United States, 1996--2011†
Figure 2. Changes in incidence of laboratory-confirmed bacterial infections, United States, 2011 compared with 2006–2008
This year's data from FoodNet provides the best measure of trends in foodborne disease from 1996–2011. It confirms that the incidence of Shiga toxin–producing Escherichia coli (STEC) O157 (25%) and Shigella (43%) infections have decreased significantly.
- The incidences of laboratory-confirmed Campylobacter, Cryptosporidium, Salmonella, Shiga toxin-producing Escherichia coli (STEC) O157 and non-O157, Shigella, and Yersinia infection were highest among children aged <5 years.
- The incidences of Cyclospora, Listeria, and Vibrio infection were highest in adults aged ≥65 years.
- Listeria infection has not decreased in more than a decade despite prior declines.
- Listeria caused one-third of all foodborne disease–related deaths. Listeria, a rare but deadly germ, hospitalized most of those infected and killed 16%.
- Thirteen percent of infections, 24% of hospitalizations, and 57% of deaths occurred in adults aged ≥65 years old.
- As a group, incidence of infections caused by six key pathogens in 2011, compared with 2006-2008, was 24% lower, including
The FoodNet 2011 data showed a lack of progress in reducing foodborne infections and highlights the need for improved prevention.
- Listeria infection, although uncommon (0.28 cases reported per 100,000 population), accounted for 33% (22 of 67) of all foodborne illness–related deaths reported in 2011.
- The incidence of Listeria infection was not significantly different in 2011 compared with 2006–2008 (Figure 2)
- Among laboratory-confirmed listeriosis cases, 95% led to hospitalization, and 16% resulted in death.
- Listeria can contaminate foods that we don't usually cook, like deli meats, sprouts, and cantaloupe.
- Listeria can grow on foods even while they are in the refrigerator.
- Incidence was 76% higher for Vibrio infection in 2011 when compared to 1996–1998.
- Vibrio infections are rare, but often serious, and are caused by eating contaminated seafood or exposing an open wound to seawater. Continued Vibrio illnesses highlight the lack of implementation of available control measures.
In comparison with the first three years of FoodNet surveillance (1996–1998), long-term trends have also been identified:
- The incidence of infections caused by Campylobacter, Listeria, STEC O157, Shigella, and Yersinia has shown sustained declines 2011.
- The overall incidence of six key foodborne pathogens (Campylobacter, Listeria, Salmonella, STEC O157, Vibrio, and Yersinia) was 24% lower.
- The incidence of Salmonella was unchanged, yet some types of Salmonella have decreased.
- The incidence of Vibrio infection was 76% higher in 2011 than in 1996–1998.
Progress in prevention of many foodborne illnesses, including Listeria infections, has been limited in recent years. Additional measures to reduce contamination of food and prevent these illnesses are needed, including:
- Regulatory agencies are working to introduce initiatives to reduce Salmonella contamination.
- Outbreak investigations to reveal gaps in food safety and drive interventions to reduce contamination.
- Effective prevention education in vulnerable populations to reduce further illness and its complications.
- Tightened standards as provided in the Food Safety Modernization Act of 2011, which are expected to reduce many important foodborne infections.
Other important pathogens transmitted commonly through food (e.g., norovirus, Clostridium perfringens, and Toxoplasma) are not tracked in FoodNet because tests to detect them are not generally available for clinical laboratories. Many of the control measures that would decrease illness caused by pathogens tracked in FoodNet would also decrease illnesses caused by pathogens not tracked presently.