What is listeriosis and what are the symptoms? All you need to know about the infection linked to recall across Ireland

Irish Times

24-07-2025

Listeriosis is in the news after an adult in
Ireland died with the rare bacterial infection
.
The
HSE's
Health Protection Surveillance Centre
is investigating the death, which was announced as the
Food Safety Authority of Ireland
(FSAI) confirmed an inquiry into an outbreak of nine cases.
The FSAI said there had been a 'voluntary precautionary recall' of 141 ready-made products 'due to a link with the outbreak'.
The recalled products, produced by Ballymaguire Foods, are sold by
Tesco
,
SuperValu
,
Centra
and
Aldi
, among other outlets. The affected meals include chicken curries, lasagnes, bolognaises, pasta bakes, cottage pies and chow meins. Affected side dishes include ready-made mashed potatoes, carrots and peas, green cabbage and pilau rice.
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What causes listeriosis?
Listeriosis is usually caused by eating food contaminated with the bacterium listeria monocytogenes. Listeria can contaminate a wide range of foods, but most infections are caused by eating chilled, ready-to-eat foods.
What are the symptoms of listeriosis?
In most people, listeriosis has no symptoms or only causes mild symptoms for a few days such as high temperature, muscle or joint pain, nausea, vomiting and diarrhoea.
However, if listeria spreads beyond the digestive system and becomes invasive, additional severe symptoms such as confusion, stiff neck, loss of balance or seizures may occur.
A listeria monocytogenes bacterium, responsible for the food-borne illness listeriosis, under the microscope. Photograph: Elizabeth White/Centers for Disease Control and Prevention via The New York Times
How long after Listeria exposure could you get sick?
The incubation period (time between initial infection and first symptoms appearing) ranges between three and 70 days. The average incubation period is three weeks after eating contaminated food.
How serious is an infection with listeria?
Listeriosis is not usually serious for most people. But some have a higher risk of serious problems, including those aged 65 and older, people with a condition that weakens their immune system and anyone who is pregnant.
If you are having treatment that weakens your immune system, such as chemotherapy, you may be at higher risk of getting seriously ill with listeriosis.
What are the complications of listeriosis?
If listeria spreads beyond your digestive system to other parts of the body, this can cause serious complications including inflammation of the heart, inflammation of the brain and spinal cord, pneumonia, sepsis, and miscarriage or preterm birth.
How is listeriosis treated?
For most people listeriosis is mild and gets better with rest and fluids. If you are at higher risk of a more serious infection, then antibiotics may be prescribed.
How does Listeria get into food?
Listeria monocytogenes is found in soil and water. Vegetables can become contaminated from the soil or from manure used as fertiliser. Animals can carry the bacterium and meat or dairy products from these animals can be contaminated. Foods may also be contaminated after processing.
The foods most often associated with listeriosis are ready-to-eat refrigerated and processed foods such as cooked and chilled meals, soft cheeses and smoked fish
The foods most often associated with infection are ready-to-eat refrigerated and processed foods such as pre-prepared cooked and chilled meals, soft cheeses, cold cuts of meat, pâtés and smoked fish.
How can I avoid listeriosis?
There are some simple things you can do to reduce your risk of getting listeriosis including keeping chilled, ready-to-eat foods cold by ensuring your fridge is working properly and is set to 5 degrees or below. You should consume ready-to-eat foods within four hours of taking them out of the fridge; eat, cook or freeze foods by their use-by date; and follow storage instructions on food labels.
Consumers should also keep raw and ready-to-eat foods separate; follow any cooking instructions on packaging, and make sure food is cooked through to the middle; wash hands, knives, and cutting boards after contact with uncooked food.