In addition to video surveillance, deputies are posted outside the barns to monitor all interactions with the horses and to collect used veterinarian supplies in sealed evidence bags pending post-race testing results.

WSJ: Vyjack's trainer puts his faith in jockey

Officials say water supplies have not been affected so far and they are closely testing samples from the river, but the public remain wary.

BBC: China fishes over 2,000 dead pigs from Shanghai river

Subsequent rounds of testing revealed adulteration in some products sold by Asda, Sodexo - which supplies food to schools, care homes and the armed forces - and the Whitbread Group.

BBC: Horsemeat scandal: Four new products test positive

They point to the European Union's decision to impose compulsory testing on all shipments of long grain rice from the US, after commercial supplies were found to be contaminated with GM strains.

BBC: NEWS | South Asia | India warned over GM rice crops