ATLANTA — Salmonella infections have not decreased during the past 15 years and have instead increased by 10%, according to “Vital Signs,” a report issued by the Centers for Disease Control and Prevention. During the same period, the report noted, illnesses caused by pathogens such as E. coli O157 have declined nearly 50% and the overall rates of six food-borne infections have been reduced by 23%.

“Although food-borne infections have decreased by nearly one-fourth in the past 15 years, more than 1 million people in this country become ill from Salmonella each year, and Salmonella accounts for about half of the hospitalizations and deaths among the nine food-borne illnesses C.D.C. tracks through FoodNet,” said Thomas R. Frieden, director of the C.D.C. “Salmonella costs hundreds of millions of dollars in direct medical costs each year. Continued investments are essential to detect, investigate, and stop outbreaks promptly in order to protect our food supply.”

The Vital Signs report summarizes 2010 data from the C.D.C.’s Foodborne Diseases Active Surveillance Network (FoodNet).

In 2010, FoodNet sites, which include about 15% of the American population, reported nearly 20,000 illnesses, 4,200 hospitalizations and 68 deaths from nine food-borne infections. Of those, Salmonella caused more than 8,200 infections, nearly 2,300 hospitalizations and 29 deaths (54% of the total hospitalizations and 43% of the total deaths reported through FoodNet). The C.D.C. estimated there are 29 infections for every lab-confirmed Salmonella infection.

The rate of E. coli O157 cases reported by FoodNet sites was 2 cases per 100,000 people in 1997 and, by 2010, had decreased to 0.9 cases per 100,000 people. The nearly 50% reduction in E. coli O157 incidence is considered significant when compared to the lack of change in Salmonella incidence.

The C.D.C. credited the reduction in E. coli to improved detection and investigation of outbreaks through the C.D.C.’s PulseNet surveillance system, cleaner slaughter methods, testing of ground beef for E. coli, better inspections of ground beef processing plants, regulatory improvements like the prohibition of STEC O157 in ground beef and increased awareness by consumers and restaurant employees of the importance of properly cooking beef.

“Thanks to our prevention-based approach to food safety, as well as industry and consumer efforts, we have substantially reduced E. coli O157 illnesses,” said Elisabeth Hagen, undersecretary for food safety in the U.S. Department of Agriculture. “This report demonstrates that we’ve made great progress. However, far too many people still get sick from the food they eat, so we have more work to do. That is why we are looking at all options, from farm to table, in-order to make food safer and prevent illnesses from E. coli, Salmonella, and other harmful pathogens.”

The pathogens included in the overall 2010 rate reduction of 23% when compared to 1996-1998 are: campylobacter, E. coli STEC O157, listeria, Salmonella, vibrio and yersinia. Rates of vibrio infection were 115% higher than in 1996-1998, and 39% higher than in 2006-2008. Most vibrio infections are the result of eating raw or undercooked shellfish.

The full report may be viewed by visiting