An outbreak of infections from Listeria monocytogenes that was traced to certain soft cheeses has been declared over by the Centers for Disease Control and prevention.

As of May 14 there were 13 confirmed patients. A dozen of the patients were so sick they had to be admitted to hospitals. One patient died. The sick people live in four states. Their illnesses started on dates ranging from Oct. 20, 2020, to March 17, 2021, with 12 illnesses occurring in 2021, according to the CDC.

The implicated cheese products are past their shelf life and should no longer be available for sale, according to an updat from the Food and Drug Administration. However, it can take up to 70 days after exposure for symptoms of Listeria infection to develop.

Because of the long incubation time, anyone who has eaten any of the implicated cheese should monitor themselves in the coming weeks for signs of infection.

The cheese was recalled in February. The queso fresco cheeses made by El Abuelito Cheese Inc. affected by the recall are: 

Sick people ranged in age from less than 1 to 75 years, with a median age of 52. Twelve people were Hispanic, and seven people were female.

Public health investigators used the PulseNet system to identify illnesses that were 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 a method called whole genome sequencing (WGS). WGS showed that bacteria from sick people’s samples were closely related genetically. This means that people in this outbreak likely got sick from the same food.

Connecticut officials collected samples of El Abuelito brand Hispanic-style fresh and soft cheeses for testing from a store wher a sick person reported buying these types of cheeses. On Feb. 19, WGS showed that the Listeria bacteria in El Abuelito brand queso fresco were closely related to the Listeria bacteria from sick people in this outbreak. This means that people likely got sick from eating this cheese.

On Feb. 19, El Abuelito Cheese Inc. recalled all queso fresco products made at their facility. They also stopped producing and distributing all their products.

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 ate any recalledproduct and developed symptoms of Listeria infection should seek medical treatment and tell their doctors about the possible Listeria exposure.

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

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, and other complications. 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.