The owner of a peanut company refused to testify to Congress on Wednesday amid the disclosure that he urged his workers to ship bacteria-tainted products, pleading with federal health officials that he should be able “turn the raw peanuts on the floor into money.“

From school lunches to nutrition bars and ice cream, the nationwide salmonella outbreak has reached deep into the American food supply — even though many people had never heard of the small company at the center of the investigation until a few weeks ago.

Kellogg Co. said Monday federal authorities have confirmed that salmonella was found in a single package of its peanut butter crackers, as a Midwestern grocer recalled some of its products because of the scare.

The latest national food safety investigation took on new urgency Friday as federal officials confirmed salmonella contamination at a Georgia facility that ships peanut products to 85 food companies.