The Telegraph reports that Public Health England (PHE) said it was investigating an outbreak of E. coli O157, which has so far affected 109 people, and said it had put in place "heightened surveillance" across the country.
Of the known cases, 102 people live in England, six in Wales and one in Scotland, with the south-west of England particularly affected.
PHE said it has "now identified that several of the affected individuals ate mixed salad leaves including rocket leaves prior to becoming unwell".
It added: "Currently, the source of the outbreak is not confirmed and remains under investigation. PHE is nowreminding people to maintain good hygiene and food preparation practices in response to the current outbreak."
