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Listeria, 2013

For questions about Listeria and food, please visit our Listeria and Food page.

For general questions about Listeria, please visit our main Listeria website.

FoodNet MMWR, 2010

What are the main findings of the FoodNet 2010 annual report?

The report shows that in 2010, Salmonella was the pathogen furthest from its national target . At 17.6 cases per 100,000 population, it is far higher than the Healthy People 2010 target of 6.8 or fewer cases per 100,000 population. It also shows that for Salmonella, there was no significant difference in 2010 rates compared with the first three years of surveillance (1996–1998). In fact, there was a 10% increase (CI= 4% to 17% decrease) when 2010 was compared with 2006–2008, that erased earlier small gains.

  • In comparison, the national 2010 target for Shiga toxin–producing Escherichia coli (STEC O157) infection (≤1.0 case per 100,000 population) was reached in 2009, and has improved again in 2010. The new Healthy People 2020 target for STEC O157 is 0.6 cases per 100,000 population.
  • In comparison with the first 3 years of FoodNet surveillance (1996–1998), sustained declines in the incidence of infections caused by Campylobacter, Listeria, STEC O157, Shigella, and Yersinia were observed. Overall the incidence of infection of six key foodborne pathogens was 23% lower. The measure does not include STEC non-O157.
  •  In 2010, we have seen a slight rise in the number of STEC non-O157 infections. Paradoxically, this increase has a positive side because it means more laboratories are testing for them.
  • In 2010, compared with 2006–2008, significant decreases in the incidence of Shigella (29%) and STEC O157 (29%) infections were observed. Significant increases were observed in the incidence of Salmonella (10%) and Vibrio (39%).
  • The reported incidences of Salmonella, Campylobacter, Shigella, Cryptosporidium, STEC O157, STEC non–O157, and Yersinia infections were highest among children aged <5 years.
  • For infections with most pathogens under FoodNet surveillance, infected persons aged >60 years are at greater risk than younger persons for hospitalization and death.

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What is FoodNet?

FoodNet is the Foodborne Diseases Active Surveillance Network. Established in 1996, FoodNet conducts detailed and accurate surveillance for Campylobacter, Cryptosporidium, Cyclospora, Listeria, Salmonella, Escherichia coli O157 and non-O157, Shigella, Vibrio, and Yersinia infections diagnosed by laboratory testing of samples from patients. It is a collaborative program among CDC, 10 state health departments, the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), and the Food and Drug Administration (FDA). FoodNet personnel located at state health departments regularly contact the clinical laboratories in Connecticut, Georgia, Maryland, Minnesota, New Mexico, Oregon, Tennessee, and selected counties in California, Colorado, and New York to find out about all infections diagnosed in residents of these areas. The FoodNet surveillance area includes approximately 46 million people or 15% of the United States population. More information about FoodNet is available at

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The incidence of Shiga toxin-producing Escherichia coli (STEC) O157 infections has decreased.  Why?

Many factors likely contributed to the decline in incidence of STEC O157 infections. One is improved detection and investigation of STEC O157 outbreaks, resulting not only in contaminated products being removed before more persons became ill but also in enhanced knowledge about preventing contamination that was used to prevent future outbreaks and illnesses. PulseNet, the national molecular subtyping network for foodborne bacterial pathogens, can detect widely dispersed outbreaks and has greatly improved the detection and investigation of multistate outbreaks. Other actions contributing to the decline include cleaner slaughter methods, microbial testing, and better inspections in ground beef processing plants; regulatory agency prohibition of contamination of ground beef with STEC O157; improvements in the FDA Model Food Code; and increased awareness in food service establishments and consumers’ homes of the risk of consumption of undercooked ground beef.

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Why hasn’t there been any decrease in the incidence of infections caused by Salmonella?

Salmonella infection is a complicated problem that is not likely to be controlled by any one measure. There are many different types of Salmonella. They are carried in the intestines of many different kinds of food animals and wild animals, and transmission of Salmonella to humans can occur in a number of different ways. Most often, Salmonella is spread through contaminated food, including foods of animal origin, raw produce, and processed foods. It can also be spread by contact with animals that carry Salmonella, as seen in recent outbreaks involving turtles, water frogs, and chicks. It can also occasionally be transmitted through contaminated water. Comparing 2010 with the first 3 years of FoodNet surveillance (1996–1998), there has been no change in the incidence of Salmonella infection. However, Salmonella infections can be prevented using approaches similar to those that were successful in reducing STEC O157. These approaches for Salmonella include monitoring the safety of ingredients, reducing contamination in factories and slaughterhouses using proven measures, and maintaining refrigeration in transport. They also include preventing food contamination. Regulatory agencies are working to introduce initiatives to reduce food contamination, particularly in poultry and produce.  Training restaurant managers in food safety and by educating consumers about preparing foods safely at home can also help. Investigating illnesses and outbreaks is important, so that contaminated products are removed before more persons become ill. Farmers, the food industry, regulatory agencies, food service, consumers, and public health authorities all have a role.

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What is CDC doing to control and prevent foodborne disease?

CDC is part of the U. S. Public Health Service, and has as a mission to use the best scientific methods and information available to monitor, investigate, control and prevent public health problems. Using the tools of epidemiology and laboratory science, CDC provides scientific assessment of public health threats. CDC works closely with state health departments to monitor the frequency of specific diseases and conducts national surveillance for them. CDC provides expert epidemiologic and microbiologic consultation to health departments and other federal agencies on a variety of public health issues, including foodborne diseases. At the invitation of state public health officials, CDC can also send a team into the field to help conduct emergency field investigations of large or unusual outbreaks. CDC researchers develop new methods for identifying and characterizing the microbes that cause disease and translate laboratory research into practical field methods that can be used by public health authorities in States and counties.

CDC is not a regulatory agency. Government regulation related to food safety is the responsibility of the Food and Drug Administration (FDA), the Food Safety and Inspection Service of the U.S. Department of Agriculture (USDA), the National Marine Fisheries Service, and other regulatory agencies. CDC maintains regular contact with the regulatory agencies.

When new food safety threats appear, CDC, in collaboration with its public health partners, conducts epidemiologic and laboratory investigations to determine the causes of these threats and how they can be controlled. Although CDC does not regulate the safety of food, CDC assesses the effectiveness of current prevention efforts. CDC provides independent scientific assessment of what the problems are, how they can be controlled, and where gaps exist in our knowledge.

Much of CDC’s effort related to foodborne illness focuses on detecting outbreaks and tracking foodborne illnesses in the US, but CDC also works to make the information it gathers available when, where, and how people need it in order to make decisions that can protect their health. Learn more about foodborne illness and CDC's prevention activities.

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What can consumers do to reduce the risk for foodborne illness?

Consumers can reduce their risk for foodborne illness by following safe food-handling and preparation recommendations and by not consuming raw or undercooked foods of animal origin such as eggs, ground beef, and poultry; unpasteurized milk, soft cheese, or juice; and raw or undercooked oysters.  They can avoid bruised or damaged fresh produce, and dented or bulging cans. Risk also can be decreased by choosing pasteurized eggs, high pressure-treated oysters, and irradiated food products. While it’s important to wash produce thoroughly, consumers should never wash meat and poultry. Everyone should also wash hands after handling raw or undercooked foods of animal origin and after contact with animals and their environments.

Food preparers should follow the easy lessons of "Clean, Separate, Cook, and Chill":

  • Clean. Wash hands, cutting boards, utensils, and countertops.
  • Separate. Keep raw meat, poultry, and seafood separate from ready-to-eat foods.
  • Cook. Use a food thermometer to ensure that foods are cooked to a safe internal temperature: 145°F for whole meats (allowing the meat to rest for 3 minutes before carving or consuming), 160°F for ground meats, and 165°F for all poultry.
  • Chill. Keep your refrigerator below 40°F and refrigerate food that will spoil.

More detailed information on food safety issues and practices, including steps consumers can take to protect themselves, is available at, and

See additional questions and answers regarding the FoodNet 2010 annual report.

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