More infants have died in an outbreak of Listeria monocytogenes infections traced to Yu Shang Food Inc. ready-to-eat meat and poultry products.

In an outbreak update, the Centers for Disease Control and Prevention reported that 19 patients have now been identified, and two babies in California and one in Tennessee have died. However, one of the babies in California — a pair of twins whose mother was also sick — did not test positive for the outbreak strain of Listeria and is therefore not included in the outbreak total.

The patients are spread across eight states. Of 17 patients with complete information available, all 17 have required hospitalization.

Seven of the illnesses are related to pregnancy. One person who was pregnant and infected with the outbreak strain of listeria recovered. Also, two sick infants who were infected recovered.

Patients range in age from less than 1 to 86 years old. 

State and local public health officials are interviewing people about the foods they ate in the month before they got sick. Symptoms of Listeria infection can develop in as little as 70 days.

People reported buying their foods from multiple stores. Among the 14 people interviewed, 11 people shopped in person and online at markets where Yu Shang food products are sold. Among the 13 people asked about precooked chicken products, eight reported eating precooked chicken products, and three specifically remembered eating Yu Shang brand ready-to-eat chicken products.

Public health investigators use the PulseNet system to identify illnesses that may be part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using whole genome sequencing (WGS). WGS showed that bacteria from sick people’s samples are closely related genetically. This suggests that people in this outbreak got sick from the same food.

The true number of sick people in this outbreak is likely higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because some people recover without medical care and are not tested for Listeria.

On Oct.21, the USDA’s Food Safety and Inspection Service (FSIS) conducted routine testing and follow-up activities of Yu Shang Food, Inc.’s finished product. Testing confirmed that the product was contaminated with Listeria. WGS showed that Listeria in pork snout products is closely related to bacteria from sick people. This means that people likely got sick from eating foods Yu Shang Food, Inc. produced.

“In response to the investigation, FSIS collected additional samples of product produced at Yu Shang Foods, Inc. and from the production environment,” according to the CDC’s outbreak update.

“The Listeria found in those samples was related by WGS to the bacteria from eight other sick people in the PulseNet database and differs from the strain found in the pork snout sample and the 11 illnesses already included in the outbreak. These illnesses were combined into one investigation.”

Yu Shang Inc. of Spartanburg, SC, has recalled more than 72,000 pounds of products related to the outbreak.

All Yu Shang ready-to-eat products produced before Oct. 28 are subject to recall. For a list of affected products, click here. Product labels can be viewed by clicking here. The products subject to recall have establishment number “P-46684” or “EST. M46684” inside the USDA mark of inspection. These items were shipped to retail locations nationwide and are available for purchase online.  

Consumers with questions regarding the recall can email ling16099@yahoo.com or contact Ling Li, Yu Shang Food Inc. plant manager, at 864-310-6313.

About Listeria infections
Food contaminated with Listeria monocytogenes may not look or smell spoiled but can still cause serious and sometimes life-threatening infections. Anyone who has eaten any recalled products and developed symptoms of Listeria infection should seek medical treatment and tell their doctors about possible Listeria exposure.

Also, anyone who has eaten any of the recalled products should monitor themselves for symptoms during the coming weeks because symptoms of listeriosis can develop up to 70 days after exposure to Listeria. 

Symptoms of Listeria infection can include vomiting, nausea, persistent fever, muscle aches, severe headache, and neck stiffness. Specific laboratory tests are required to diagnose Listeria infections, which can mimic other illnesses. 

Pregnant women, the elderly, young children, and people such as cancer patients who have weakened immune systems are particularly at risk of serious illnesses, life-threatening infections, other complications, and death. Although infected pregnant women may experience only mild, flu-like symptoms, their infections can lead to premature delivery, infection of the newborn, or even stillbirth.

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