Listeria: Everything you need to know as deli meat outbreak kills at least one

At least one person has died and 16 others have fallen ill across six states after being infected with listeria, a dangerous bacteria that contaminates food and causes listeriosis, according to the US Centers for Disease Control (CDC).

The public health body said on Wednesday that the cases were linked to the bacteria’s spread through deli meats and cheeses, including brie and camembert, and were recorded between April 2021 and September 2022 in New York, New Jersey, Maryland, Massachusetts, Illinois and California.

Seven of the cases were detected in New York and five of the people affected reportedly said they had purchased meat at a NetCost Market store where listeria had previously been found in October 2021.

The CDC said it believes other delis are likely to have been hit by the current outbreak and said it is working with the federal Food and Drug Administration (FDA) and the Department of Agriculture to trace the spread in the hope of containing it.

The ages of those taken ill so far ranged from 38 to 92, the CDC said, and 11 of them had Eastern European backgrounds.

Thirteen of those infected were hospitalised and one person had suffered a miscarriage.

“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,” the CDC said.

According to the FDA, the Listeria monocytogenes bacteria (first identified in 1911 but named in 1940 to “honour” British surgeon Joseph Lister, who recognised the importance of sterilising equipment before attempting invasive operations) enters the human body after contaminated food is eaten or handled or contaminated surfaces are touched.

The institution’s website explains: “After a person ingests Listeria monocytogenes, the bacteria grow quickly in the liver and then move into the bloodstream and can invade many places in the body, including the brain, membranes surrounding the brain and spinal cord, the gastrointestinal tract and the bloodstream.”

The CDC states that around 160,000 people contract listeriosis in the US every year and the disease poses the greatest threat to the over-65s, pregnant women and those with a pre-existing condition that has left their immune system weakened.

As an invasive illness, the disease can be severe and its most common symptoms are fever and flu-like symptoms such as fatigue and muscle aches, although headaches, stiff necks, confusion, loss of balance and even seizures are possible.

As an intestinal illness, where symptoms are likely to be milder, diarrhoea and vomiting are the probable result, lasting around one-to-three days.

Anyone experiencing symptoms they believe to have been caused by listeria is advised to seek medical aid.

In invasive cases, listeriosis is usually treated with a course of antibiotics but that may well not be necessary in its intenstinal form unless the risk is deemed to be severe, although those suffering from the latter version of the virus will need to ensure they rehydrate properly to compensate for the loss of fluid.

The CDC warns that while listeria outbreaks in the 1990s were largely traceable due to processed meats and hot dogs, more recent cases have also stemmed from other foodstuffs like soft cheeses, raw celery, sprouts and melons, unpasteurised milk and ice cream.

Those who believe they have purchased products that might have been affected are advised to clean their refrigerators and any surfaces the foods might have touched with hot soapy water.