E coli outbreak may be caused by mixed salad

People are being told to wash salad leaves thoroughly, with public health officials concluding that mixed salad is probably the cause of a new E. coli outbreak.

So far, says Public Health England (PHE), 109 people have been identified as suffering from this particular strain - 102 in England, six in Wales and one in Scotland - with the south-west of England particularly affected.

And it's discovered that rocket leaves may be to blame.

"PHE has been working to establish the cause of the outbreak and has now identified that several of the affected individuals ate mixed salad leaves including rocket leaves prior to becoming unwell," says Dr Isabel Oliver, director of PHE's field epidemiology service.

"Currently, the source of the outbreak is not confirmed and remains under investigation."

E. coli O157 infection can cause a range of symptoms, from mild diarrhoea to bloody diarrhoea with severe abdominal pain - or even more serious medical conditions such as kidney failure.

The main sources of the bug are undercooked meat or raw leafy vegetables - one outbreak three years ago was believed to be caused by Sainsbury's watercress, for example.

It can be caught by eating contaminated food, but can also be passed from one person to another if hand and toilet hygiene is poor.

"We urge people to remove any loose soil before storing vegetables, and thoroughly wash all vegetables (including salads) that will be eaten raw unless they have been pre-prepared and are specifically labelled 'ready to eat'," says Dr Oliver.

People should also be very careful about washing their hands with soap and water after using the toilet, before and after handling food and after contact with any animals.

But, Dr Oliver warns, "These measures may reduce the risk of infection from any E. coli contaminated vegetables, fruit and salad, but will not eliminate any risk of infection completely."

While it's not yet confirmed that the rocket really is the culprit, PHE is working to pin down the source of the outbreak.

"PHE has put in place heightened surveillance for this strain of E. coli and is carefully monitoring the reporting of cases across the entire country," Dr Oliver says.

"To assist with this investigation to help us find the source, we have convened a national outbreak control team who will also ensure all necessary control measures are put in place."