The Federal authorities are investigating Nestle's Danville, Va., plant that makes refrigerated cookie dough which is believed to be related to a new national outbreak of a bacteria-triggered illness, according to media reports on Monday.

Federal microbiologists and food safety investigators have descended on the Danville plant, trying to crack a scientific mystery surrounding a national outbreak of illness from bacteria E. coli, a deadly strain of bacteria, which has been linked to the product.

Nestle USA Friday recalled its refrigerated cookies, one kind of Nestle's famous Toll House products, after federal health officials linked the dough to infections from the bacteria in 66 people in 29 states, including five in Washington. The recall does not affect other Toll House products, including ice cream that contains raw Toll House dough.

Consumers were asked to throw away the dough or, to get a refund, return it to the store where it was purchased. The FDA advised against baking the dough because bacteria could be transferred to hands and preparation surfaces.

FDA spokesman Michael Herndon said officials were confident that Nestle refrigerated dough products caused the outbreak.

The FDA is continuing to investigate the source of the contamination.

"Was it a contaminated ingredient, and if so what?" said Dr. David Acheson, the FDA's associate commissioner for foods. "Or was it a problem that occurred inside the facility during processing?"

Spokeswoman Laurie MacDonald for Nestle USA in Glendale, Calif., a unit of Switzerland-based Nestle SA, said the company has temporarily stopped making the refrigerated dough products while the FDA investigates the Danville plant.

"We hope to resume production as soon as possible," she said.

(Agencies via Xinhua June 23, 2009)