Pregnant women and those with weakened immune systems have been issued a warning by the Food Standards Agency (FSA) over disease causing bacteria.

The government agency is urging vulnerable people to ensure they thoroughly cook foods which may contain Listeria monocytogenes.

The bacteria can survive and even grow under refrigeration and can cause Listeriosis which can last up to several weeks depending on the severity.

Symptoms include fever, vomiting and headaches, with some cases even resulting in convulsions.

In rare cases, the infection can lead to meningitis.

The warning covers Enoki mushrooms, sometimes labelled as Enokitake, Golden Needle or Lily Mushrooms.

They are tall, white, thin-stemmed mushrooms, which are commonly used across Asia. While they are usually served cooked, they are occasionally served raw, such as in salads or, as a garnish.

The FSA was alerted to the presence of Listeria monocytogenes in Enoki mushrooms in Canada and the USA in 2021.

As of yet, there have been no known cases of listeriosis linked to the mushrooms in the UK, however, analysis of recent FSA and local authority partner sampling and testing data found the presence of Listeria monocytogenes in 13 of 40 samples of Enoki mushrooms tested, sometimes at high levels.

Tina Potter, head of incidents at the FSA, said: “The Food Standards Agency (FSA) and Food Standards Scotland (FSS) advice is that Enoki mushrooms can be contaminated with Listeria monocytogenes and should be stored in the fridge and handled carefully.

The Northern Echo: Enoki mushroomsEnoki mushrooms (Image: FSA)

“You should properly clean any surfaces and utensils you’ve used to prepare them and wash hands. Those who are pregnant or have weakened immune systems should cook Enoki mushrooms thoroughly before eating them as this will destroy any Listeria monocytogenes present, which can cause serious illness in vulnerable consumers.”

The FSA is working with Local Authorities and Port Health Authorities to advise food businesses and importers of the risks associated with Enoki mushrooms and remind them of the food safety and labelling requirements.

If you have eaten these products recently, you do not need to do anything, unless you get symptoms of the infection. These include a high temperature of 38C and above, aches and pains, chills, feeling and being sick, or diarrhoea.

Contact NHS 111 or your GP surgery if you are unwell and pregnant or have a weakened immune system and you think you could have listeriosis.