Accepted Food Poisoning Figures Based on Think Tank Estimation Model

Frequently, when food safety stories appear in news reports, they are accompanied by the statement that about 9,000 Americans die every year from food poisoning. No source is ever given for this number. Recently, Dan Wilson, a reporter for the Appleton, Wis., Post-Crescent decided to research the genesis of the 9,000-deaths statistic and to report his findings in the Columbia Journalism Review. What Wilson found is that the number is an estimate developed by the Council for Agricultural Science and Technology (CAST), a think tank in Ames, Iowa.

In 1994, CAST issued a report, "Foodborne Pathogens: Risks and Consequences." The task force charged with studying the foodborne pathogen issue had relied upon two researchers - Dr. Ewen Todd, a microbiologist, and Dr. John Bennett, a medical doctor - to come up with annual estimates of illnesses and deaths caused by food poisoning. According to Wilson, "They produced wildly different numbers," with Todd estimating 12,581,630 cases resulting in 523 annual deaths, and Bennett estimating 6,485,755 cases resulting in a higher 8,982 deaths. "Both scientists had used mathematical models to arrive at an estimate," said Wilson, and "neither model was based on known cases." When the report was issued, CAST adopted Bennett's 9,000 figure. Todd's fatality estimate was not used.

Wilson contacted the Centers for Disease Control (CDC) to check the agency's annual Summary of Notifiable Diseases, which lists the numbers of recorded deaths by category. According to Wilson, "The differences between those numbers and Bennett's were striking." According to Bennett, for example, 1,000 people die annually from trichinosis, a pork parasite. According to the CDC, only one trichinosis death has been recorded in the past ten years. Bennett posited 28 deaths per year from typhoid fever, which is carried by shellfish; the CDC recorded a total of 21 over a ten-year period. (The CDC has not been tracking E. coli deaths long enough to have a number.)

When Wilson contacted Dr. Tanya Roberts, co-chairman of CAST's task force and employee of USDA's Economic Research Service, she told him, "Notifiable deaths are horribly under-reported." What the CDC has, "is a legal record, not a medical record," she said.

Roberts conceded that some of Bennett's numbers may be inflated: "Until we do a good analysis I would say we don't know for sure. I don't know where the truth lies, and I don't think anyone else does ... . I don't think Todd is accurate and I don't think Bennett is accurate. The truth is somewhere else, or in between." Still, Roberts said she leans towards the higher number, because "Bennett's science is the best to date."

In a letter to the Columbia Journalism Review, Roberts said the numbers were "generally ... considered by CAST task force members to be estimates based on defensible assumptions."

Nonetheless, says Wilson, "numbers that were based on one researcher's best guess have achieved the status of unassailable truth simply by being run through several spin cycles until they were adopted without attribution by many reporters." He also found in the course of his investigation a phenomenon he calls "unattributed-numbers bracket creep." As examples, Wilson cites a Nov. 24, 1997 U.S. News & World Report story that says, in part, "Each year up to 81 million Americans suffer a foodborne illness; 9,100 die." From USA Weekend, Jan. 23, 1998, Wilson found the following: "Deaths from tainted food topped 10,000 last year ... ." In neither story were sources cited for the rising numbers, he said.

The fear for the safety of the U.S. food supply is an issue now on the minds of more consumers than ever before. Food poisoning is a topic to which many can relate, and which many have experienced first hand. The numbers may have been inflated or exaggerated to capture headlines, but no matter what the "real" numbers are, they have captured the minds of consumers.