Lambs, pigs, goats, cattle, ponies and rabbit droppings at a Surrey farm at the centre of an E. coli outbreak have tested positive for the bacteria.
Experts from the Veterinary Laboratories Agency (VLA) said 33 of 102 samples were likely to contain the O157 strain of the infection.
The Health Protection Agency (HPA) said the number of E. coli cases linked to Godstone Farm had risen to 67.
Eight children remain in hospital in a "stable or improving condition".
The VLA said it visited Godstone Farm on 7 and 16 September and White Post Farm at Farnsfield, near Mansfield, Nottinghamshire, on 18 September, at the request of the HPA.
'Bacteria in faeces'
It added: "We found that 33 of 102 samples taken on [7 September] were likely to be verocytotoxin producing E. coli VTEC O157."
But the VLA said the infectious bacteria was not contained in pond water samples, six samples of sandpit sand or smaller "pet animals".
During its second visit to Godstone Farm scientists found two samples of E. coli O157 on the floor of the main barn.
Nigel Gibbens, Defra chief Veterinary officer, said: "Joint HPA and VLA investigations have confirmed the presence of E. coli O157 bacteria in faeces from a wide range of animals on a premises in Surrey.
"The bacterium is known to have the capacity to infect a wide range of animals but the VLA advise that E. coli O157 has more commonly been found in ruminants, such as cattle, sheep and goats.
"The VLA is working closely with the HPA to assist with the ongoing investigations."
The VLA said five of the 121 samples collected from animals at White Post Farm at Farnsfield, near Mansfield, Nottinghamshire, yielded "presumptive VTEC O157, representing cows and calves, with no public access, and housed sheep and goats."
The Godstone Farm closed on 12 September and its sister farm, Horton Park Children's Farm in Epsom, was also shut because of "unsatisfactory" hygiene arrangements.
The outbreak at Godstone Farm near Redhill is believed to have started on 8 August.
No cases of E. coli O157 infection have been linked to the Epsom site.
White Post Farm was closed after two visitors were confirmed to be suffering from the same strain of E. coli.
The World of Country Life in Exmouth, Devon, closed its petting farm and deer ride on Friday on the advice of the Health Protection Agency (HPA).
E. coli - which causes symptoms include diarrhoea and vomiting - can be especially dangerous in young children because they cannot tolerate much fluid loss. It can lead to kidney failure.
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