Leafy greens such as lettuce, spinach and kale accounted for the most food-borne illnesses nationwide from 1998 through 2008, the Centers for Disease Control and Prevention reports.
Dairy products accounted for the most hospitalizations. The most deaths were linked to poultry.
The study isn't meant to be a "risk of illness per serving" list for consumers, said Patricia Griffin, a food-borne disease expert at the CDC who was the senior author of the report. The statistics are meant to help regulators and the food industry target efforts to improve the safety of food.
"The vast majority of meals are safe," she said, so don't let the numbers for leafy greens keep you from eating vegetables. "Eating them is so important to a healthy diet. They're linked to reduced risk of heart attacks, stroke and cancer."
The study looked at 4,887 outbreaks that caused 128,269 illnesses, hospitalizations and deaths when the food that caused them was known or suspected. It appears Tuesday in the journal Emerging Infectious Diseases.
Epidemiologists at the CDC found that leafy greens accounted for 23% of illnesses and dairy products 14%. However, when they looked only at hospitalizations, the lineup was different: Dairy products were responsible for 16% of hospitalizations followed by leafy vegetables at 14% and poultry 12%. For deaths, poultry accounted for 19%, then dairy products at 10%.
The overall number of deaths was small: 277 people died from food-borne illnesses linked to poultry and 140 from illnesses linked to dairy products during those years.
While the statistical details won't be all that helpful to consumers, it's "essential" for government agencies and the food industry as they work to make food safer, Griffin said.
That's especially the case now that implementation of the Food Safety Modernization Act is underway. The act requires the Food and Drug Administration to focus its regulatory efforts on the highest-risk food products. Until now, they were hard to identify.
Griffin cautions that the dairy product numbers are misleading. Many of the outbreaks linked to dairy products involve unpasteurized milk and cream, but the vast majority of Americans drink and eat only pasteurized dairy products.
"The weight of the raw milk outbreaks is making it look as if dairy is a bigger source of illness than we actually think it is," she said.
A study published last year that looked at 13 years of outbreaks linked to dairy products found that unpasteurized milk, cheese and cream were 150 times more likely to cause food-borne illness outbreaks than pasteurized dairy foods and that such outbreaks had a hospitalization rate 13 times higher than those involving pasteurized dairy products.