Animal droppings collected from a farm in Surrey have tested positive for E coli.
Positive samples came from ewes, lambs, pigs, goats, cattle, ponies and rabbits.
Eleven of those samples were “indistinguishable” from the 0157 strain of bacteria which had lead to 67 people falling ill, eight of whom are still in hospital.
Tests were also carried out on 16 September on “pet animals” including rabbits and ducks.
While none of those samples contained the strain, faeces from the floor of the main barn tested positive.
Professor Peter Borriello, VLA chief executive, said experts were working to identify exactly how the infections had been caused.
The discovery came as the family of a “seriously ill” girl thought to have been infected during a trip to Godstone announced it was taking legal action against the farm for negligence.
Personal injury lawyer Jill Greenfield said she hoped to meet representatives of the farm and the Health Protection Agency as soon as possible to establish if anyone was at fault.
“It’s not simply about financial compensation, although that is a part of it,” she told the BBC.
“Some of these children could have long-term medical conditions for which they will need financial compensation.
“But it’s far too early to tell with any of them because E coli is a bit of a slow burner.”
Three other farms across the UK have also closed amid E coli concerns.
Horton Park Children’s Farm, in Epsom, the sister farm to Godstone Farm, shut over hygiene concerns, while White Post Farm in Nottinghamshire closed after two cases of the E coli 0157 strain were confirmed and two potential cases emerged.
The World of Country Life farm, in Exmouth, Devon, voluntarily closed its deer run and animal petting areas on the advice of the Health Protection Agency after three children who visited the farm contracted E coli.