Stewart Parnell, owner of Peanut Corp. of America, the company that has been held responsible for the salmonella outbreak has refused to testify to the Congress that he had ordered the workers to ship the tainted peanut butter.

About 600 people fell sick because of the salmonella outbreak and nine people died due to the contamination. It has also resulted in the largest recall. More than 1800 items had been recalled due to the contaminated peanut butter in the market.

During the hearing, a lab tester testified that the company was aware of the salmonella at its Georgia plant in 2006. But inspite of the discovery, Parnell went ahead with the sale of the product.

The panel has also released emails obtained by its investigators which also reveal that Parnell ordered products identified as tainted with salmonella be shipped. Parnell also remarked that tests discovering the contaminated food were "costing us huge." Lawmaker Henry Waxman has accused Parnell of caring about profit over safety.

A federal investigation has been ordered against Parnell.