CDC: US sees no progress in battling Salmonella

Jun 7, 2011 (CIDRAP News) – An annual update today viewed as the nation's report card on food safety showed that Escherichia coli O157:H7 infections continue to decline, but measures to cut Salmonella infections haven't made any headway.

At a press conference today, federal officials unveiled 2010 data from FoodNet, a surveillance system that gathers information on confirmed foodborne illnesses from 10 states or parts of states. Tom Frieden, MD, director of the US Centers for Disease Control and Prevention (CDC), told reporters that the bottom line is: Foodborne illnesses, especially those involving Salmonella, are far too common.

He said cuts to public health departments in the tough budget times could undermine the nation's ability to prevent and respond to food contamination threats. "The outbreak in Germany serves as a reminder of the challenges posed by foodborne illnesses," Frieden said.

Factoring in 2010 data, the rate of E coli O157:H7 cases has decreased nearly 50% since 1997, according to the report. In contrast, the CDC, writing in Morbidity and Mortality Weekly Report (MMWR), said that Salmonella infections have increased 10% in recent years.

Federal officials said the reason why it's so difficult to reduce foodborne illnesses from Salmonella is because the pathogen is found in such a wide variety of foods, which requires a host of different control tactics.

Dr Michael Taylor, deputy commissioner for foods at the US Food and Drug Administration (FDA), said the FoodNet report is the best metric available to determine if the food safety community is making progress against the diseases. "We still have a lot of work ahead of us, especially with Salmonella," he said. "And it will take more than one intervention to bring the incidence of Salmonella down."

Officials said it's too soon to tell if a new shell egg safety rule that went into effect for larger producers last summer has had any effect on lowering the number of Salmonella infections. Taylor said that, after the rule is fully implemented in 2013 for smaller producers, officials project infections from Salmonella enterica subtypeEnteritidis to drop by nearly 60%.

In 2010, the leading Salmonella serotype was Enteritidis (22%), followed by Newport (14%), and Typhimurium (13%), according to the report. Compared with the years 2006 to 2008, the incidence of Enteritidis was 36% higher and the incidence of Newport was 47% higher. The level for Typhimurium did not change significantly.

The number of Vibrio cases, usually linked to eating contaminated shellfish, continued to rise and are 115% higher than in the late 1990s. Officials aren't sure why the rates continue to climb. Among Vibrio isolates with species information, the most common was parahaemolyticus (57%), the type that causes milder infection, whereas V vulnificus, the cause of more serious disease, was responsible for 13% of infections. (The percentages didn't change much from 2009.)

On a more positive note, the overall reduction of foodborne diseases caused by six key pathogens (Campylobacter, E coli O157:H7, Listeria, Salmonella, Vibrio, and Yersinia) have fallen by 23% over the past 15 years, the report said.

FoodNet collected reports of 19,089 illnesses, 4,247 hospitalizations, and 68 deaths from foodborne illnesses in 2010. Salmonella was the most common infection and was linked to the highest number of hospitalizations and deaths.

Dr Elizabeth Hagen, under secretary for food safety at the US Department of Agriculture (USDA), attributed the great strides in reducing E coli O157:H7 illnesses to improvements in trace-back policies and meat sampling. She said the agency's Food Safety and Inspection Service (FSIS) continues to explore more ways to further protect consumers. "The pathogens evolve, and we must do the same," she said.

She said the FSIS is developing a proposal to declare six non-O157:H7 strains of Shiga-toxin producing E coli (STEC) as adulterants in meat and is working with the Office of Management and Budget on some remaining technical issues. "We all want to get this right," she said.

Frieden said that, despite the lack of progress on driving down the number of Salmonella infections, he is encouraged that food safety officials can make some headway with new initiatives and reforms included in the Food Safety Modernization Act that was signed into law earlier this year.

CDC. Vital signs: incidence and trends of infection with pathogens transmitted commonly through food—foodborne disease active surveillance network, 10 US sites, 1996-2010. MMWR 2011 Jun 7;early release [Full text]

See also:

Jun 7 CDC press release

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