A deadly, international Listeria outbreak that Canadian officials linked to diced chicken appears to be over in the U.S., according to federal officials who will not name any entity or food as having any connection with the 13-state outbreak.

Two people died in the United States during the 18-month outbreak. It sickened at least 24 people, with 22 of them admitted to hospitals, according to an update posted today by the U.S. Centers for Disease Control and Prevention.

The U.S. patients were confirmed to have infections from the outbreak strain of Listeria monocytogenes. The strain matched that of samples isolated from sick people in Canada.

Officials posted a number of recalls in Canada involving diced chicken because it was associated with the illnesses.

“Based on the investigation findings, Rosemount brand cooked diced chicken was identified as a likely source of the outbreak. Rosemount cooked diced chicken was supplied to institutions — including cafeterias, hospitals, and nursing homes — where many of the individuals who became sick resided or visited, before becoming ill,” according to a Nov. 1 update from the Public Health Agency of Canada (PHAC).

No recalls or warnings about any food were posted in relation to the listeriosis outbreak in the United States.

The Canadian Food Inspection Agency (CFIA) posted a food recall warning for Rosemount brand cooked diced chicken on Aug. 18. During the agency’s food safety investigation, the CFIA identified additional affected products and updated food recall warnings have been issued.

A spokesperson for the CDC in the United States could only provide comments that were almost identical to the outbreak update.

“During the investigation, Canada did have evidence indicating a specific brand of cooked diced chicken was supplied to institutions where people became sick. While whole-genome sequencing showed that the Listeria bacteria making people sick in the U.S. and Canada were closely related genetically, the U.S. investigation did not implicate a specific source of the outbreak,” according to the CDC spokesperson.

As for whether the implicated chicken was tested in the United States, the CDC says it can’t answer those questions and referred Food Safety News to the U.S. Department of Agriculture because it handled that part of the investigation.

A spokesperson from the USDA’s Food Safety and Inspection Service (FSIS) discussed two recalls by Tip Top Poultry Inc. in August and September in the United States. The agency spokesperson said it “does not have any laboratory confirmation that connects Tip Top Poultry’s recalled products to the Listeria outbreak in Canada or the United States.” 

“To clarify, Tip Top Poultry Inc.’s Aug. 20 and Sept. 28 recalls resulted from two separate incidents where Canadian authorities notified the company that some of its products tested positive for Listeria. These two instances, however, are independent of each other and were verified as unrelated to any illness,” the FSIS spokesperson told Food Safety News.

“Concerning the investigation into the recent Listeria monocytogenes illnesses, FSIS evaluated all information relating to case patients and conducted extensive product testing of diced chicken and other products, but did not find evidence linking any specific FSIS regulated establishment or products to the illnesses. . . As of today (Nov. 8), FSIS does not have any laboratory confirmation that connects Tip Top Poultry’s recalled products to the Listeria outbreak in Canada or the United States.”

U.S. outbreak details
No new sick people have been confirmed in the U.S. outbreak since the CDC’s initial outbreak notice on Aug. 23, according to the agency’s update today.

Confirmed outbreak victims reported illness onset dates beginning July 20, 2017, through Aug. 1 this year. The outbreak investigation, which used whole-genome sequencing to test the Listeria, showed that bacteria isolated from ill people were closely related genetically. This means that people in this outbreak were more likely to share a common source of infection.

The victims ranged in age from 35 to 92 years. Sixty-three percent of ill people were female. Of 23 ill people with information available, 22 hospitalizations were reported.

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 develops symptoms of Listeria infection should seek medical treatment and tell their doctors about possible Listeria exposure.

It can take up to 70 days after exposure to Listeria for symptoms of listeriosis to develop. Special lab tests are required to diagnose listeriosis.

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.

Editor’s note originally posted Nov. 3: At this time, the credibility of the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) is not to be trusted. Both agencies have shown a reckless disregard for the public’s right to know, and their reliability going forward remains suspect. For the next six weeks, Food Safety News will publish this note above on every story involving the FDA or CDC.

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