Earlier, ABC News reported that the chemical was on wheat imported from China. However, at the news conference Commissioner Patrick Hooker and Donald Smith, dean of veterinary medicine at Cornell University, said that they could not confirm the source of the contamination.
Hooker also said that the toxin is not registered for legal use in the U.S. for rodent control.
They also said that the Food and Drug Administration and Menu Foods had been notified of the finding. Both stressed that the results were just one step in a process to determine how the food became contaminated.
Smith said the news conference was called to provide information to the public, as well as other researchers looking into the situation.
They said that they tested final products, not individual ingredients.