Public health officials have announced another recall of diced chicken as outbreak investigators in Canada and the U.S. continue to look for the source of Listeria monocytogenes behind an outbreak.

This time it is again diced chicken from Rosemount Sales and Marketing, which distributed the implicated chicken to retailers, possibly nationwide in Canada, but for certain in the provinces of British Columbia, Manitoba and Ontario, according to a recall notice posted by the Canadian Food Inspection Agency (CFIA).

“The food recall warning issued on Aug. 21 has been updated to include additional product information,” according to the recall notice. “This additional information was identified during the CFIA food safety investigation. . . during its investigation into a foodborne illness outbreak.”

The recall now includes Rosemount brand “cooked diced chicken mostly dark 13 mm – ½” (#18305)” in 4.54-kilogram packages with the UPC number 2 06 20263 12002 0 and a pack date of “01/21/19.”

Consumers should not consume and distributors, retailers and food service establishments such as hotels, restaurants, cafeterias, hospitals and nursing homes should not sell or use the recalled products, the CFIA advised.

The Public Health Agency of Canada is investigating an outbreak of Listeria monocytogenes infections linked to diced chicken. Patients in the Canadian outbreak have been lab confirmed to have been infected with a Listeria strain “closely related genetically to the Listeria making people sick in the United States,” the U.S. Centers for Control and Prevention reported yesterday. CDC reports.

Also, whole genome sequencing, sometimes called DNA fingerprinting, shows the sick people in the United States are infected with bacteria that is closely related, meaning people in this outbreak are more likely to share a common source of infection, which could be a food product. 

It is often particularly difficult for outbreak investigators to determine the source of foodborne Listeria infections because it can take up to 70 days after exposure for symptoms to develop. At that point most ill people cannot recall all of the foods and beverages they have consumed that could have been the source of the bacterium.

As of Friday, in the United States a total of 24 people infected with the outbreak strain of Listeria monocytogenes had been confirmed in 13 states. Specimens were collected from ill people from July 20, 2017, through Aug. 1 this year. All but three of the outbreak patients became sick from March through Aug. 1 this year. 

Canadian officials are reporting similar information.

“As of Aug. 23, there have been seven confirmed cases of Listeria monocytogenes illness in three provinces: British Columbia (1), Manitoba (1) and ontario (5). Individuals became sick between November 2017 and June 2019,” according to the Public Health Agency of Canada.

Six of the Canadian patients have been hospitalized. People in Canada who became ill are between 51 and 97 years of age. The majority of cases, 86 percent, are female.

“The collaborative outbreak investigation was initiated because of an increase of Listeria illnesses that were reported in June 2019. Through the use of a laboratory method called whole genome sequencing, two Listeria illnesses from November 2017 were identified to have the same genetic strain as the illnesses that occurred between April and June 2019,” according to the public health officials in Canada.

“It is possible that more recent illnesses may be reported in the outbreak because of the period of time it takes between when a person becomes ill and when the illness is reported to public health officials. In national Listeria monocytogenes outbreak investigations, the reporting time period is usually between four and six weeks.”

In the U.S., yesterday’s notice from the CDC said consumers, retailers, distributors and foodservice operations such as restaurants and hospitals do not need to avoid any particular food at this time.

However, Canadian officials notified their U.S. counterparts that a sample of Tip Top Poultry has been confirmed positive for Listeria. The Georgia company initiated a recall of more than 135,000 pounds of chicken products. Poultry in the United States is regulated by the USDA’s Food Safety and Inspection Service (FSIS).

“What is perplexing is why there is no confirmation by FSIS and CDC of the source of the outbreak,” said Bill Marler, managing partner at Marler Clark and publisher of Food Safety News.

“. . . our own CDC has said that whole genome sequencing shows that bacteria isolated from ill people in both Canada and the U.S. are closely related genetically — presumably that applies to the Tip Top Poultry Listeria sample as well. This means that people in this outbreak are more likely to share a common source of infection.”