Listeria can cause an illness called listeriosis. While the infection is considered rare it has the potential to be serious, particularly if you’re pregnant or have a weak immune system.
At the end of last week, supermarkets recalled bags of frozen vegetables over fears they could contain the bacteria.
The products, sold at Tesco, Lidl, Aldi, Sainsbury’s and Waitrose, have since been recalled.
Listeria can contaminate a wide range of foods, but it is of most concern in chilled ready-to-eat foods that do not require further cooking or reheating. The Food Standards Agency says there are seven foods to be wary of.
These include: cooked sliced meats, cured meats, smoked fish, cooked shellfish, blue veined and mould-ripened soft cheese, pate, and pre-prepared sandwiches and salads.
To reduce the risk of listeria when preparing food at home, the food hygiene body says it’s important to keep raw and ready-to-eat foods separate to avoid cross-contamination.
You should also wash fruit and vegetables thoroughly, keep chilled ready-to-eat foods cold – make sure your fridge is working properly and is set to 5C or below, and always use foods by their use-by date.
Follow the storage instructions on the label and use opened foods within two days unless instructions on the packaging say otherwise.
Ready-to-eat food must be eaten within four hours of being taken out of the fridge.
Also make sure to cook or reheat foods until they are piping hot right through, and ensure that you follow manufacturer’s instructions in the preparation of all foods.
So what are the symptoms of listeriosis to watch out for, and when should you seek to get medical help?
There are five signs to watch out for, according to the NHS. These include a high temperature of 38C or above, aches and pains, chills, feeling sick or vomiting, and diarrhoea.
If you’re pregnant and think you have listeriosis you should call your midwife straight away. You may need a blood test to check for the infection.
You’ll be given antibiotics if you have listeriosis because it could cause serious problems like a miscarriage if not treated.
The health body says you should also ask for an urgent GP appointment if you think you have listeriosis and you have a condition that weakens your immune system (like diabetes).
You should also contact your doctor immediately if you think you have listeriosis and you’re having treatment that weakens your immune system (like chemotherapy).
Likewise, contact your GP if you think your baby might have listeriosis.
If the infection is not treated, severe listeriosis can cause serious infections like meningitis in babes and people with a weak immune system.
If you experience a severe headache and stiff neck, discomfort when looking at bright lights, fits, sudden confusion, or a rash that doesn’t fade when a glass is rolled over it, you should call 999 or go to A&E.
These could be symptoms of meningitis caused by listeriosis and this needs to be treated in hospital straight away.