An E. coli outbreak that sickened at least 42 people and shuttered Chipotle restaurants in Oregon and Washington was another recent reminder of the impact of food-related or foodborne illness. In the next year, studies suggest that nearly one in 30 Americans — 10 million people — will get sick from a foodborne pathogen, and one in 250,000 will die.
The U.S. economy will take a $15.5 billion dollar hit through lost income, lost revenue, healthcare-related costs and some intangibles, like "pain and suffering," according to the U.S. Department of Agriculture.
Research shows the most common foodborne pathogen is norovirus, which is the leading cause of gastroenteritis. The most deadly is listeria; though it is rare, with just 123 confirmed cases in 2013, 24 led to death. The most expensive is salmonella, which is quite common — 7,277 cases in 2013, but with a small fraction (127) resulting in death.
How worried should Americans be about the safety of the food supply? Which foods are most likely to get Americans sick? A deep dive into the data offers a look at where the risks lie.
Which foods carry health risks
To identify the most dangerous foods, the Emerging Pathogens Institute, a research institute at the University of Florida, compiled a greatest hits of dangerous pathogen/food pairings. Using a methodology that combined the likelihood of contracting an illness and the illness’s severity to calculate total disease burden, the group identified a Top Ten list of combinations.
Number one, by a long shot, is campylobacter, a bacterium found in poultry.
Next come toxoplasma in pork, listeria in deli meats, and salmonella in poultry. Although leafy vegetables are responsible for the greatest number of foodborne illnesses by a wide margin (nearly a quarter of the total), it’s not until you get to number 8 on the Top Ten list that produce, paired with salmonella, makes an appearance.
The top pairings don't necessarily map to the major outbreaks of disease; only four of the top ten outbreaks in 2014 were from pairings on the list. J. Glenn Morris, director of the Emerging Pathogens Institute, told Fortune that, outbreaks are "a small fraction" of the total number of foodborne illnesses. In most cases, foodborne illnesses are limited to a small group of people, which makes it difficult for authorities to track.
The financial toll
When it comes to calculating economic impact, cost scales up with the pathogen's virulence. Norovirus, according to Morris, is very common, but is likely only to make anyone who contracts it sick with, perhaps, diarrhea or nausea for a couple of days so costs of medical care and lost productivity are relatively small.
With listeria, though, or toxoplasmosis, “the number of cases is small, but the risk of death or long-term disability is significant, so you get long-term financial impact.” According to Michael Batz, also with the Emerging Pathogens Institute and one of the authors of the paper calculating the $15.5 billion impact of foodborne illness, "there's also a social welfare value to a life," and the estimate of intangibles like pain and suffering that he and his co-authors use is $8.7 million per life lost. Value attributed to those lives are the lion’s share (83%) of the total $15.5 billion estimate.
Salmonella’s ubiquity, as well as the rare possibility of causing death, earned it the Most Expensive Pathogen title, with an annual $3.7 billion dollar price tag. Toxoplasma and listeria, though far less common, earn the #2 and #3 slots respectively because they are more deadly than salmonella.
But the food supply is still safe
Still, Morris calls the American food supply “basically safe" and says that overall, foodborne illnesses are not on the rise ("basically flat").
He says the estimate of almost 10 million food-borne illnesses per year from known pathogens is "reasonable" because it's an extrapolation of hard, pathogen-by-pathogen data. The Center for Disease Control (CDC) has made a larger estimate of 48 million illnesses and 3,000 deaths but that estimate comes from self-reported data of diarrheal disease, which tends to be less reliable, Morris says.
For something that costs thousands of lives and billions of dollars, shouldn't there be a better handle on the data? "We don’t have an optimal means of monitoring occurrence of foodborne disease,” Morris argues. The responsibility for tracking foodborne diseases lie with state health departments, while the USDA is responsible for ensuring the safety of meat, poultry, and eggs, and the FDA is responsible for everything else. Though Morris acknowledges the U.S. record on food safety is on par with other developed nations, he adds, “every other developed country has one agency responsible for food safety. We really have something of a mess.”
USDA Secretary Tom Vilsack is on record as favoring a system in which a single agency is responsible for food safety. A spokesperson for the FDA, when asked for comment by Fortune, said only that the agency supports "a more integrated national food safety system." The FDA recently finalized new rules that are designed to prevent outbreaks. The rules require farmers to regularly train workers on best practices, and the rules also make importers accountable if their foods don't meet U.S. standards of safety. The government estimates about 52% of fresh fruit and 22% of fresh vegetables are imported.
This story was updated. An earlier version incorrectly named the Emerging Pathogens Institute and incorrectly identified what number produce fell on the list of food risks.