An outbreak of the bacteria listeriosis across Europe has prompted the Food Standards Agency to release a health warning over a huge list of frozen foods provided by the manufacturer Greenyard Frozen UK Ltd.

According to the European Food Safety Authority, some 47 cases have been identified since 8 June and up to nine people have died of the infection, which has prompted 43 products to be recalled from UK supermarkets including Tesco, Lidl, Aldi, Waitrose and more.

If you’re worried about the infection or which products are affected, we’ve got a full breakdown of what the bacterial infection is, how it can be caught and the measures you can take to protect yourself from it.

What is listeria (listeriosis)?

Listeriosis is a rare bacterial infection found within food that’s caused by the listeria bacteria.

It usually passes on its own, but can cause more serious problems if you’re pregnant or have a weak immune system.

How can you catch listeriosis?

According to the NHS you can catch the infection from many different types of foods, but the main causes are:

• unpasteurised milk

• dairy products made from unpasteurised milk

• soft cheeses, like camembert and brie

• chilled ready-to-eat foods, like prepacked sandwiches, pâté and deli meats

• Pre-packed frozen foods

In this particular instance the bacteria has been found in a number of frozen foods grown and packaged by a particular brand known as Greenyard Frozen UK Ltd.

What is causing this current outbreak?

The Food Standards Agency warns that the frozen sweetcorn produced by this company is where there is a heightened risk of catching it.

In particular the FSA warns against eating frozen food before you’ve properly cooked it.

Which products are affected?

The Food Standards Agency has released an official list of every product that is at risk, to see all of them click here.

What are the symptoms of listeriosis?

For most people listeriosis has no symptoms or only causes mild symptoms for a few days such as:

• a high temperature of 38C or above

• aches and pains

• chills

• feeling sick or vomiting

• diarrhoea

However if you’re pregnant, the NHS urges that you should always call your midwife if you think you have listeriosis.

In addition if you think you have listeriosis and have a condition that can result in a weakened immune system, such as diabetes, you should contact your GP immediately. This also applies if you think you have the bacterial infection and are undergoing treatment such as chemotherapy.

Finally, if you have a baby and you’re worried that they have the condition you should again contact your GP immediately as listeriosis can cause severe infections like meningitis in babies.

How can you avoid listeriosis?

The NHS lists some simple things you can do to avoid increasing your risk of catching listeriosis.

You should wash your hands regularly with soap and water as well as washing fruit and vegetables before eating them. If you’ve bought ready meals, make sure you’re storing them as instructed by the manufacturer.

Finally, make sure all food that you cook, in particular frozen vegetables, is steaming hot all the way through.

There is one piece of key advice from the NHS, which is don’t eat food after its use-by date, even if it looks and smells normal.