Outbreak of Salmonella Infections Linked to Ground Beef

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Published on November 1, 2019 at 4:00 PM ET

CDC, public health and regulatory officials in several states, and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) are investigating a multistate outbreak of Salmonella Dublin infections linked to ground beef.

A single, common supplier of ground beef has not been identified. This investigation is ongoing and CDC will update the public as more information becomes available.

What You Need to Know
At A Glance
Photo of ground beef.

CDC is not advising that consumers stop eating thoroughly cooked ground beef, or that retailers stop selling ground beef.

Always handle ground beef carefully and cook it thoroughly to prevent food poisoning. This outbreak is a reminder that raw and undercooked ground beef can have germs in it that can make you sick and can contaminate areas where food is prepared.

  • Don’t eat raw or undercooked ground beef.
  • Cook ground beef to an internal temperature of 160°F. Use a food thermometerexternal icon to make sure the meat has reached this safe internal temperature. You can’t tell whether meat is safely cooked by looking at it.
    • For hamburgers, insert thermometer through the side of the patty until it reaches the middle.
    • Place the thermometer in the thickest part of the meat for other items.
  • Ask that ground beef hamburgers and mixtures be cooked to 160°F internal temperature when ordering at a restaurant.
  • Wash hands with soap and water for at least 20 seconds after touching raw meat. Wash items that came into contact with raw ground beef, such as countertops, utensils, dishes, and cutting boards, with hot, soapy water or in a dishwasher.
Latest Outbreak Information
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  • 10 people infected with the outbreak strain of Salmonella Dublin have been reported from six states.
    • A total of 8 ill people were hospitalized, including one death reported from California.
  • Epidemiologic and laboratory evidence indicate that ground beef is a likely source of this outbreak. A single, common supplier of ground beef has not been identified.
    • In interviews, ill people report eating different types and brands of ground beef purchased from many different locations.
    • Laboratory testing identified the outbreak strain of Salmonella Dublin in repackaged leftover ground beef collected from an ill person’s home in California.
    • This outbreak investigation is ongoing and CDC will update the public if more information becomes available.
Food Safety and Ground Beef
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Handling ground beef:

  • Keep raw meat separate from foods that won’t be cooked before eating.
  • Wash your hands with soap and water for 20 seconds after touching raw meat and before touching other kitchen items.
  • Thoroughly wash countertops, cutting boards, plates, and utensils with hot, soapy water or a bleach solution after they come in contact with raw meat or its juices, to avoid contaminating other foods and kitchen items.

Cooking ground beef:

  • Don’t eat raw or undercooked ground beef.
  • Cook ground beef hamburgers and mixtures such as meatloaf to an internal temperature of 160°F. Use a food thermometerexternal icon to make sure the meat has reached a safe internal temperature. You can’t tell whether meat is safely cooked by looking at it.
  • For hamburgers, insert the thermometer through the side of the patty until it reaches the middle.
  • For foods such as meatloaf, place the thermometer in the thickest part of the meat.
  • For casseroles and for sauces that contain ground beef, such as spaghetti sauce or sloppy joe sandwiches, check the temperature in several places.
  • After cooking ground beef, refrigerate within 2 hours and use within 3 to 4 days.
  • When ordering at a restaurant, ask that ground beef hamburgers and mixtures be cooked to an internal temperature of at least 160°F.

Storing ground beef:

  • Refrigerate or freeze raw ground beef within 2 hours after purchase.
  • If you refrigerate raw ground beef, use within 1 or 2 days.
  • Store ground beef in a plastic bag on the lowest shelf of your refrigerator.
  • If you break large packages of ground beef into smaller packages for freezing:
    • Wash your hands with soap and water for 20 seconds after touching the meat or its packaging, and before touching other surfaces.
    • Use hot, soapy water to clean the area where you divided the ground beef, including kitchen counters and utensils.
    • Label your packages with the date they were placed in the freezer and where you purchased the ground beef.

Thawing ground beef:

  • The best way to safely thaw ground beef is in the refrigerator. Cook or refreeze within 1 or 2 days.
Symptoms of Salmonella Infection
Illustration of a person with stomach pain.

  • Most people infected with Salmonella develop diarrhea, fever, and stomach cramps 12 to 72 hours after being exposed to the bacteria.
  • The illness usually lasts 4 to 7 days, and most people recover without treatment.
  • In some people, the illness may be so severe that the patient needs to be hospitalized. Salmonella infection may spread from the intestines to the bloodstream and then to other places in the body.
  • Children younger than 5 years, adults 65 years and older, and people with weakened immune systems are more likely to have a severe illness.
Investigation Details

November 1, 2019

CDC, public health and regulatory officials in several states, and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) are investigating a multistate outbreak of Salmonella Dublin infections linked to ground beef.

Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting is performed on Salmonella bacteria isolated from ill people by using a standardized laboratory and data analysis method called whole genome sequencing (WGS). CDC PulseNet manages a national database of these sequences that are used to identify possible outbreaks. WGS gives investigators detailed information about the bacteria causing illness. In this investigation, WGS showed that bacteria isolated from ill people were closely related genetically. This means that people in this outbreak are more likely to share a common source of infection.

As of November 1, 2019, a total of 10 people infected with the outbreak strain of Salmonella Dublin have been reported from 6 states. A list of the states and the number of cases in each can be found on the Map of Reported Cases page.

Illnesses started on dates ranging from August 8, 2019, to September 22, 2019. Ill people range in age from 48 to 74 years, with a median age of 68. Eighty percent of ill people are male. Of nine ill people with information available, eight (89%) were hospitalized, and one death has been reported in California. In five (50%) ill people, Salmonella was found in samples of blood, which indicates their illnesses may have been more severe. Salmonella Dublin is known to commonly cause more severe illnesses than other Salmonella strains, particularly in older people.

Illnesses might not yet be reported due to the time it takes between when someone becomes ill and when the illness is reported. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

Whole genome sequencing analysis did not identify any antibiotic resistance in 16 bacterial isolates from 10 ill people and 6 food specimens. Testing of clinical isolates using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) is underway.

Investigation of the Outbreak

Epidemiologic and laboratory evidence indicates that ground beef might be contaminated with Salmonella Dublin and is making people sick. At this time, the investigation has not identified a single, common supplier of ground beef.

In interviews, ill people answered questions about the foods they ate and other exposures in the week before they became ill. Of eight people interviewed, six (75%) reported eating ground beef at home. This percentage is significantly higher than results from a survey pdf icon[PDF – 787 KB] of healthy people in which 40% of respondents reported eating any ground beef at home in the week before they were interviewed. Ill people reported buying ground beef from various stores.

Laboratory testing identified the outbreak strain of Salmonella Dublin in repackaged leftover ground beef collected from an ill person’s home in California. The outbreak strain of Salmonella Dublin has also been identified in six samples of raw beef products from slaughter and processing establishments. Samples from slaughter and processing establishments were collected as part of FSIS’s routine testing under the Salmonella performance standards. WGS showed that the Salmonella strain from these samples was closely related genetically to the Salmonella from ill people. These results provide more evidence that people in this outbreak got sick from eating ground beef. At this time, the investigation has not identified a single, common supplier of ground beef.

This outbreak investigation is ongoing and CDC will update the public if more information becomes available.