Listeria: The sympoms, the risks and how to avoid it

What is listeria?

Listeria, or rather the illness officially known as listeriosis, occurs when people are infected with the listeria monocytogenes bacterium. While rarer than food-poisoning pathogens such as salmonella and E coli, listeria outbreaks are generally more serious. In the US around 260 people die a year on average from it, according to the Centres for Disease Control and Prevention. In the UK the Health Protection Agency recorded 156 cases last year.

What causes it?

In humans it is usually transmitted by contaminated food. Outbreaks generally involve uncooked meat or vegetables, or milk or cheese which have not been pasteurised. However, it can affect cooked and processed foods if the bacterium is present in a factory and enters later, for example during the packaging process. Listeria is hardy – it can remain in a kitchen or factory for long periods, and can even grow at fridge temperatures.

Who is at risk?

For healthy adults listeria is generally not a significant risk – exposure to it might cause mild flu-like symptoms or stomach problems. However, it is significantly more dangerous for those with weakened immune systems, such as older people, the very young, or those with cancer, diabetes, Aids or other significant illnesses. Pregnant women are particularly susceptible – they are 20 times more likely than other healthy adults to get listeria. While the effect on them may be mild it can cause miscarriage, stillbirth or a serious infection for a new baby. This is why pregnant women are urged not to eat high-risk foods such as patés and soft cheeses.

What can the effects be?

More serious infections generally cause serious gastrointestinal and flu-like symptoms, often with muscle ache and a stiff neck, or sometimes confusion and loss of balance. This can then lead to a meningitis-like inflammation around the brain or septicaemia. Listeria is generally treated with antibiotics, which need to be administered quickly in serious cases.

How can it be prevented?

Meats should be thoroughly cooked, and raw fruit and vegetables washed. Uncooked meat should be stored separately, and products containing unpasteurised milk avoided. Another key element is good kitchen hygiene, both keeping hands and equipment clean, and consuming even refrigerated leftovers within a few days.

http://www.guardian.co.uk/