Multistate Outbreak of Salmonella Typhimurium Infections Linked to Peanut Butter, 2008–2009
Posted January 23, 2009
This outbreak appears to be over. However, Salmonella is an important cause of human illness in the United States. More information about Salmonella, and steps people can take to reduce their risk of infection, can be found on the CDC Salmonella Web Page.
CDC’s Role During a Multi-State Foodborne Outbreak Investigation
Most foodborne outbreaks are identified and investigated by local and state health departments. CDC provides consultation on some of those, as well as assistance on request for outbreaks that are particularly large, unusual, or severe.
In recent years, large multi-state foodborne outbreaks have become more common, because better surveillance identifies outbreaks that would previously have been missed and because an increasingly centralized food supply means that a food contaminated in production can be rapidly shipped to many states causing a widespread outbreak.
The Department of Health and Human Services’ Centers for Disease Control and Prevention (CDC) works with a number of public health partners, including state, county, and city health departments, and the federal regulatory agencies, such as the United States Food and Drug Administration (FDA), the United States Department of Agriculture - Food Safety and Inspection Service (USDA/FSIS) , and the Environmental Protection Agency. During a multi-state foodborne disease outbreak, CDC serves as lead coordinator between public health partners to detect the outbreak, define its size and extent, and to identify the source.
CDC maintains and monitors several disease surveillance and outbreak detection systems in collaboration with public health partners. PulseNet, a sophisticated outbreak detection system, is a national surveillance network of CDC, state, and local public health laboratories and federal food regulatory agency laboratories. PulseNet performs pulsed-field gel electrophoresis (“DNA fingerprinting”) on disease-causing bacteria that may be foodborne to find clusters of cases that might be related.
Once a potential multi-state outbreak has been detected, CDC’s OutbreakNet Team engages to investigate it. By collaborating with public health partners, OutbreakNet leads the epidemiologic investigation of multistate outbreaks. OutbreakNet coordinates communications among states and may lead epidemiologic studies. These are studies to develop a short list of suspect foods or other exposures (“hypothesis generation”), to identify food exposure associated with illness (“case control studies”), and to determine how the food became contaminated. CDC also provides assistance in the field to any state requesting it. CDC’s laboratories maintain PulseNet surveillance to identify new cases, conduct advanced laboratory tests of disease-causing microbes, test suspect foods, and provide technical support to OutbreakNet and public health partners as part of the investigation.
Once a contaminated food source has been identified, public health action to control the outbreak can be taken by regulatory agencies such as FDA and USDA/FSIS. At this stage, CDC continues to investigate potential sources of illness and monitors for additional illnesses to determine when the outbreak is over. CDC also advises the public about what they can do to protect themselves, advises the medical community about how to treat the infections, and works closely with the regulatory agencies and industry to learn how to prevent similar outbreaks in the future.