Most of more than 1,500 reported outbreaks of foodborne diseases between 2009 and 2010 were attributed to salmonella-tainted foods or norovirus, CDC researchers wrote in the Morbidity and Mortality Weekly Report. Eggs contaminated with salmonella accounted for 2,231 foodborne illnesses during the study period, and other causes were E. coli O157 in beef and Campylobacter in unpasteurized dairy products.