The figures are the most accurate to date due to better data and methods used. The data were published this week in two articles in the journal Emerging Infectious Diseases.

The papers provide the most accurate picture yet of what foodborne pathogens are causing the most illness, as well as estimating the proportion of foodborne illness without a known cause. The reports are the first comprehensive estimates since 1999 and are CDC's first to estimate illnesses caused solely by foods eaten in the United States.

"We've made progress in better understanding the burden of foodborne illness and unfortunately, far too many people continue to get sick from the food they eat," said CDC Director Thomas Frieden, M.D, M.P.H. "These estimates provide valuable information to help CDC and its partners set priorities and further reduce illnesses from food."

CDC's new estimates are lower than in the 1999 report. The difference is largely the result of improvements in the quality and quantity of the data used and new methods used to estimate foodborne-disease. For example, it is now known that most norovirus is not spread by the foodborne route, which has reduced the estimate of foodborne norovirus from 9.2 to approximately 5.5 million cases per year. Because of data and method improvements, the 1999 and current estimates cannot be compared to measure trends.

CDC's FoodNet surveillance system data, which tracks trends among common foodborne pathogens, has documented a decrease of 20 per cent in illnesses from key pathogens during the past 10 years. However, these FoodNet pathogens make up only a small proportion of the illnesses included in the new estimates.

Of the total estimate of 48 million illnesses annually, CDC estimates that 9.4 million illnesses are due to 31 known foodborne pathogens. The remaining 38 million illnesses result from unspecified agents, which include known agents without enough data to make specific estimates, agents not yet recognized as causing foodborne illness, and agents not yet discovered. In both the 1999 and current estimates, unspecified agents were responsible for roughly 80 per cent of estimated illnesses.

"Foodborne illnesses and deaths are preventable, and as such, are unacceptable," said FDA Commissioner Margaret A. Hamburg, M.D. "We must, and can, do better by intensifying our efforts to implement measures that are prevention-oriented and science-based. We are moving down this path as quickly as possible under current authorities but eagerly await passage of new food safety legislation that would provide us with new and long overdue tools to further modernize our food safety programme."

Among the additional findings for foodborne illness due to known pathogens:

• Salmonella was the leading cause of estimated hospitalizations and deaths, responsible for about 28 per cent of deaths and 35 per cent of hospitalizations due to known pathogens transmitted by food.
  
  
• About 90 per cent of estimated illnesses, hospitalizations, and deaths were due to seven pathogens: Salmonella, norovirus, Campylobacter, Toxoplasma, E.coli O157, Listeria and Clostridium perfringens.
  
  
• Nearly 60 per cent of estimated illnesses, but a much smaller proportion of severe illness, was caused by norovirus.

"People expect food to nourish them, not to harm them. So we need to intensify efforts to decrease the number of illnesses and deaths due to foodborne diseases," said Christopher Braden, M.D., director of CDC's Division of Foodborne, Waterborne, and Environmental Diseases. "We now know more than ever what pathogens are causing the most harm, and we will continue our work to help protect people from these illnesses. Much that remains unknown about how and why people get sick and we are committed to learning more in the future."

CDC continues to encourage consumers to take an active role in preventing foodborne infection by following safe food-handling and preparation tips of separating meats and produce while preparing foods, cooking meat and poultry to the right temperatures, promptly chilling leftovers, and avoiding unpasteurized milk and cheese and raw oysters.