Outbreak Investigation Updates by Date

Final Update

Posted January 29, 2019 at 1:00 PM ET

This outbreak appears to be over. In general, people who are at higher risk for Listeria infection should avoid eating hot dogs, lunch meats, cold cuts, other deli meats (such as bologna), or fermented or dry sausages unless they are heated to an internal temperature of 165°F or until steaming hot just before serving. Learn more about how you can take steps to prevent Listeria infection.

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November 21, 2018

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 Listeria monocytogenes infections.

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 Listeria bacteria isolated from ill people by using a technique called whole genome sequencing (WGS). CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. WGS performed on bacteria isolated from ill people showed that they were closely relatedly genetically. This means that people in this outbreak are more likely to share a common source of infection.

As of November 20, 2018, four people infected with the outbreak strain of Listeria monocytogenes have been reported from four states. A list of the states and the number of cases in each can be found on the Map of Reported Cases page.

Listeria specimens from ill people were collected from July 1, 2017, to October 24, 2018. Ill people range in age from 35 to 84 years, with a median age of 60 years. All four ill people are female, and all four ill people were hospitalized. No deaths have been reported.

Illnesses might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 10 weeks. Please see the Timeline for Reporting Cases of Listeria Infection for more details.

Investigation of the Outbreak

Epidemiologic and laboratory evidence indicates that pork products from 165368 C. Corporation, doing business as Long Phung Food Products in Houston, TX is a likely source of this outbreak.

In interviews, ill people answered questions about the foods they ate and other exposures in the four weeks before they became ill. Four people were interviewed and all four reported eating Asian-style foods. Three ill people reported shopping at stores where Long Phung Food Products are sold.

Whole genome sequencing results of samples collected at the Long Phung Food Products facility showed that Listeria identified in the facility was closely related genetically to Listeria from ill people. These results provide more evidence that ill people became sick from eating contaminated pork products.

On November 20, 2018, 165368 C. Corporation, doing business as Long Phung Food Products recalledExternal ready-to-eat pork products because they might be contaminated with Listeria bacteria. Recalled pork products were produced from May 21, 2018, through November 16, 2018. Consumers should return them to the store for a refund or throw them away. Restaurants and retailers should not serve or sell recalled Long Phung Food products.

This investigation is ongoing, and CDC will provide updates when more information is available.