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Each year, about 1 in 6, or about 48 million Americans, get sick from eating contaminated food. Foodborne illnesses, commonly called food poisoning, cause nearly 128,000 people to be hospitalized and about 3,000 people to die of complications annually. The elderly, very young children, and people with weakened immune systems or pre-existing conditions are particularly vulnerable.

Public health officials investigate outbreaks of foodborne illnesses to identify the causes, prevent more people from getting sick, and determine how to stop similar outbreaks from occurring in the future. Though most of the time the cause of food poisoning cannot be determined, those cases that are identified and confirmed by laboratory testing can be reported and tracked by local and state health departments as well as the Centers for Disease Control and Prevention (CDC). Viruses are the most common causes, but bacteria and toxins are also major sources of the illnesses.

Last month, the CDC, the U.S. Food and Drug Administration (FDA) and the USDA's Food Safety and Inspection Service (FSIS) released a new report on an improved method for analyzing outbreak data to determine which foods are responsible for illnesses caused by four major foodborne bacteria. The specific office to issue the report was the Interagency Food Analytics Collaboration (IFSAC), a partnership of the three agencies, which focuses on the process called foodborne illness source attribution. The improved analytic method uses new food categories that match the categories used to regulate food products and also puts an emphasis on more recent outbreak data.

Based on the new method, the report estimates that four bacteria, Salmonella, Escherichia coli O157 (E. coli O157), Listeria and Campylobacter, are responsible for 1.9 million cases of foodborne illness in the United States every year. These four were chosen, according to the report, because of the frequency or severity of the illnesses they cause and because there are interventions, such as safe food handling, that can help reduce their occurrence.

For the report, data were used from close to 1,000 foodborne illness outbreaks between 1998 and 2012 in order to determine which food categories were most likely to make people sick with one of the four bacteria. Among the key findings:

  • More than 80% of E. coli O157 illnesses were linked to either beef or to vegetable row crops, such as leafy vegetables.
  • A majority of Salmonella cases (77%) were linked to a broad range of foods, such as produce with seeds (e.g., tomatoes, cucumbers), eggs, fruits, chicken, beef, sprouts and pork.
  • Nearly 75% of Campylobacter illnesses were linked to dairy foods (66%), particularly raw milk or cheese processed from raw milk, and chicken (8%).
  • More than 80% of Listeria illnesses were linked to fruit (50%) and dairy (31%), although there were limited data and much of that came from a single outbreak—linked to cantaloupes—in 2011.

The three agencies releasing the report hope that IFSAC's work on foodborne illness will help prevent future outbreaks. Future work may include combining the new estimates with other data in order to recommend new priorities for improving food safety and help create new regulations as well as performance standards and measures.

According to the CDC, you can help protect yourself and family members from becoming ill with a foodborne illness through some important precautions:

  • Wash hands, surfaces and utensils often when preparing food
  • Wash fruits and vegetables
  • Separate raw and fresh food both inside the refrigerator and during food preparation
  • Cook food to the recommended temperature and refrigerate uneaten food promptly

If you think you or someone you know has become ill through contaminated food, you can submit a report through


(February 24, 2015) CDC, Federal Partners Develop Improved Method for Attributing Foodborne Illness. Available online at through Accessed March 17, 2015.

(February 2015) Foodborne Illness Source Attribution Estimates for Salmonella, Escherichia coli O157 (E. coli O157), Listeria monocytogenes (Lm), and Campylobacter using Outbreak Surveillance Data. Available online at through Accessed March 17, 2015.

(Page last updated September 6, 2013) Prevention and Education. Available online at through Accessed March 17, 2015.

(Page last updated January 8, 2014) Estimates of Foodborne Illness in the United States. Available online at through Accessed March 17, 2015.

(Page last updated January 27, 2014) Public Health Resources: State or Territorial Health Departments. Available online at through Accessed March 17, 2015.