U.S. states and companies don't have to disclose the fact that tests have found salmonella or other contaminants in food, a top federal official told the Senate Agriculture Committee Thursday.

The statement by Dr. Stephen Sundlof, food safety director for the U.S. Food and Drug Administration (FDA), drew a response from Senator Saxby Chambliss.

"That's one of the very serious loopholes we need to plug."

Committee chairman Tom Harkin agreed. "To say that food safety in this country is a patchwork system is giving it too much credit. Food safety in America has become a hit-or-miss gamble, and that is truly frightening," he said.

Sundlof was testifying about the salmonella outbreak traced to a Georgia peanut plant. More than 550 people have been infected, and the outbreak has led to at least eight deaths.

The FDA has come in for criticism over its handling of the salmonella cases, but Sundlof said U.S. federal law does not require disclosure if companies find contamination through private tests, or if states find outbreaks.

He said the FDA only learned about the positive tests at Peanut Corp. of America recently, even though they date back to 2007. The company shipped products after getting negative results.

Initially chicken was suspected in the outbreak after the U.S. Centers for Disease Control and Prevention found signs in November.

Talks in early January between federal and Minnesota regulators suggested peanut butter may have been the problem.

By Jan. 9, FDA inspectors were at Peanut Corp.'s Georgia plant, which has now been identified as the source of the salmonella.

The company denies any wrongdoing.

With files from the Associated Press