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Overview of Attribution of Foodborne Illness

Estimating the number of illnesses associated with specific food sources is called foodborne illness source attribution 1. These analyses are the logical extension of our prior analyses estimating the number, or burden, of foodborne illnesses, hospitalizations, and deaths in the US.

Determining the sources of foodborne illness is an important part of identifying opportunities to improve food safety. Having a better sense of the relationship between contaminated foods and illness supports food safety along the entire food production chain—from fields where food is grown to cutting boards in kitchens.

The web pages in this section provide background on why Attribution is important to consumers and to those working to make our food safer. It will also describe the approaches, data and partnerships CDC  is working to enhance.

Why Attribution?

The 2011 Estimates of Foodborne Illness told us that roughly 48 million people (1 in 6) get sick each year from food eaten in the United States. More than 9 million of these illnesses are accounted for by major pathogens [1 page] we track.

Vital Signs graphic: 1 and 6 people get food poisoning To prevent foodborne illness, food safety regulators, industry, and consumers need to know the major food sources. By attributing the estimated number of foodborne illnesses to particular categories of foods (or food commodities), we can target measures to prevent food contamination and set goals for improvement.

Regulators and industry use this information to design, target, and implement more informed measures to prevent food contamination. Consumers can use this information to better apply safe food practices.

Attribution of Foodborne Illness Tells Us Which Foods Are Involved

Chart: Contributions of different food categories to domestically aquired illnesses and deaths, US, 1998-2008.Attribution estimates can be used to design new practices and prevention strategies to safeguard our food. For example, regulatory agencies can use attribution estimates to conduct risk analyses required in the rulemaking process.

Attributing illness to foods is a challenge for several reasons. There are thousands of different foods, and we eat many varieties even in a single meal. For the vast majority of foodborne illnesses, we do not know what food is responsible for someone getting sick.

One way we approach attribution estimation is to use the data collected during foodborne outbreak investigations. Outbreak investigations provide direct links between foodborne illnesses and the foods responsible for them. Data from foodborne disease outbreaks are an important foundation to develop attribution estimates. To improve our understanding of the food sources of illnesses beyond outbreaks, however, additional data and analyses are needed.

Food is Complicated

Mother and daughter with grocery cartVisit any grocery store and you will see that there are hundreds of different foods. A person may eat many different types of food in a single meal. For scientists studying food sources responsible for illnesses, it would be simpler if we ate foods one at a time, like eating an apple by itself. But we often mix many different ingredients together from many types of foods and eat them together as one dish, such as an apple pie made with flour, spices, and sugar.

Just as a grocery store has different aisles and sections with related types of foods, individual foods can be categorized into groups. It is important to categorize foods in ways that are helpful to agencies that investigate outbreaks, regulate food safety, and inform consumers. Industries that produce foods also find this useful.

CDC has developed a basic list of 17 food categories, also called commodities, that are logical groupings based on the nature of the food source, like fish, beef, or leafy vegetables 2.

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Figure 1. Hierarchy of 17 Food Commodities Used in Outbreak Analysis


1Pires SM, Evers EG, van Pelt W, et al. Attributing the human disease burden of foodborne infections to specific sources. Foodborne Pathog Dis 2009;6:417-24

2Painter JA, Ayers T, Woodruff R, Blanton E, Perez N, Hoekstra RM,et al. Recipes for foodborne outbreaks: a scheme for categorizing and grouping implicated foods. Foodborne Pathog Dis. 2009;6:1259–64

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