Heather Preen died after contracting E.coli 0157 on a family holiday. Two other children who were at the resort in Dawlish Warren are also ill with the same strain. One is seriously ill in hospital.
Three further confirmed E.coli infections in children in the south Devon area are also being investigated, but they are thought to have been caused by a different strain of the bacteria.
Heather and the two other children were not staying at the same holiday camps, but all played on the same beach, which has a Blue Flag, the top EU category for cleanliness.
Heather's father, Mark Preen, 37, from Birmingham, said that despite the Blue Flag award he believed the state of the beach was to blame. "There are three children from three different parts of the country who came here at the same time and caught the disease," he said. "The beach seems to be the common factor. It is not as clean as it used to be. We first went there about five years ago and it was really clean.
"But there was a lot of rubbish and mess on it this time - sanitary towels and stuff that comes from sewage pipes."
However, the South and West Devon Health Authority said that in two weeks of intensive examinations of food outlets, the beach, the sea and water supplies, it had no positive results.
Heather died earlier this month. At first her family thought she was suffering from a minor stomach bug, but it developed rapidly into kidney failure and brain damage. She died in her parents' arms at the Royal Bristol Hospital for Sick Children after they decided to switch off the life support machine.
Heather's mother urged other parents to be on the look-out for symptoms such as sickness and diarrhoea. "I don't want any other children to go through what Heather and we experienced," said Julie Preen, 32.
Dr Jim O'Brien, the director of public health for the South and West Devon Health Authority, said: "Extensive investigations have been undertaken and all necessary precautions are in place. Although the source of the infection has not been identified there have been no further confirmed cases and it is extremely unlikely there is any increased risk to the public."
Teignbridge District Council, said that Dawlish Warren was an award- winning beach which had attracted no complaints about hygiene this summer.Reuse content