ATLANTA – In 2007, a total of 1,097 foodborne disease outbreaks were reported to the Centers for Disease Control and Prevention (C.D.C.), according to an analysis conducted by the agency. State investigators said 21,244 illnesses and 18 deaths were a result of the outbreaks. The report also provides the most recent data on how many illnesses were linked to specific types of foods.

"Knowing more about what types of foods and foodborne agents have caused outbreaks can help guide public health and the food industry in developing measures to effectively control and prevent infections and help people stay healthy," said Chris Braden, acting director of the C.D.C.'s Division of Foodborne, Waterborne and Environmental Diseases.

Despite health officials' efforts, the cause of an outbreak – either the food or the foodborne agent responsible – often cannot be determined or confirmed, according to the C.D.C. This most commonly is the case when the outbreak is small. Of 1,097 reported outbreaks in 2007, 497 (45%) confirmed that one foodborne agent was responsible and in an additional 12 outbreaks more than one foodborne agent was responsible. Thus, in more than half of the outbreaks, a foodborne agent was not identified. Norovirus was the most-frequently confirmed foodborne agent (39%), followed by Salmonella (27%).

Foodborne-disease outbreaks due to norovirus occur most often when infected food handlers do not wash their hands well after using the toilet; outbreaks due to Salmonella occur most often when foods are contaminated with animal feces. Contaminated foods are often of animal origin, such as beef, poultry, milk or eggs. But any food, including vegetables, may become contaminated. Thorough cooking kills Salmonella.

In the 235 outbreaks where one food commodity was identified, the largest number of illnesses listed poultry (691 illnesses), beef (667 illnesses) and leafy vegetables (590 illnesses) as the cause, the study states. The C.D.C. tracks 17 food commodity categories. A full listing of the number of illnesses associated with each of the categories is available at:

. The full report, "Surveillance for Foodborne Disease Outbreaks – United States, 2007" appears in this week?s edition of C.D.C.'s Morbidity and Mortality Weekly Report, and is available online at

Direct access to the Foodborne Outbreak Online Database (F.O.O.D.), a searchable database of outbreaks reported to C.D.C. between 1998 and 2007 is available at: