WASHINGTON — Lawmakers reacted angrily Thursday when told that food makers and state safety inspectors are allowed to keep tests results secret.

That keeps federal health officials in the dark even when products have been contaminated by salmonella or other dangerous bacteria.

"I'd like to see some people go to jail," Sen. Patrick Leahy, D-Vt., said during a Senate Agriculture Committee hearing on a deadly salmonella outbreak linked to a Georgia peanut plant that has sickened more than 550 people and killed at least eight.

Federal law does not require reporting of contaminants if companies receive private test results showing them or states find them in their inspections, said Dr. Stephen Sundlof, food safety director for the Food and Drug Administration.

"That's one of the very serious loopholes we need to plug," said Sen. Saxby Chambliss, a Georgia Republican and the committee's ranking minority member.

Sundlof defended the FDA's handling of the current outbreak, but also noted gaps in the country's food safety system that hamper the agency's efforts. The FDA learned only weeks ago that the Peanut Corp. of America had received a series of private tests dating back to 2007 showing salmonella in their products from the Georgia plant, but later shipped the items after obtaining negative test results.

"We would like to have as much information as possible" from food makers, Sundlof said.

Leahy said food manufacturers should face possible jail time and other tough penalties to beef up compliance with federal food safety rules. "Fines won't do it," he said.

Sundlof pointed out that a federal criminal investigation of the outbreak is under way.

Also Thursday, the Department of Agriculture suspended Peanut Corp. from participating in government contract programs for at least a year. Secretary Tom Vilsack also removed Stewart Parnell, president of the company, from USDA's Peanut Standards Board.

"The actions of (Peanut Corp. of America) indicate that the company lacks business integrity and business honesty, which seriously and directly hinders its ability to do business with the federal government," said David Shipman, Acting Administrator of USDA's Agricultural Marketing Service.

Peanut Corp. has denied any wrongdoing in the outbreak and has said its Blakely plant had received regular visits and inspections from state and federal authorities in 2008 and had gotten a "superior" rating from an independent inspection.

Sundlof told senators the FDA was hot on the trail of a Georgia processor even before they were certain that peanuts were to blame for hundreds of illnesses.

The first signs of the outbreak were detected in November by the Centers for Disease Control and Prevention. But disease detectives initially suspected chicken was the culprit in clusters of salmonella infections that states were reporting.

On Jan. 7 and 8, after discussions between federal and Minnesota authorities, peanut butter was added to the short list of suspects when some people who had gotten sick reported eating peanut butter in nursing homes and at an elementary school. On Jan. 8, the FDA visited an Ohio distributor for Peanut Corp. of America.

The next day federal inspectors were at the company's Blakely, Ga. facility, which ultimately was identified as the source of the food poisoning. That same day, Jan. 9, Minnesota health officials found salmonella in an open container of peanut butter made at the plant. On Jan. 10, Minnesota made a positive match to the salmonella strain that caused the outbreak.

Sundlof said the FDA has made many improvements in its food-safety system, and acted quickly in the current outbreak.

"The American food supply continues to be among the safest in the world," Sundlof said.

Lawmakers, however, may not be reassured. They are concerned about the state of the national food safety system, a collaboration between the FDA, CDC and authorities in each state. As the list of recalled items containing peanut products surpasses 1,000, lawmakers are vowing to press for stronger food safety laws and more money for inspections.

"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," said Agriculture Committee Chairman Sen. Tom Harkin, D-Iowa. "It's time to find the gaps in the system and remedy them."

Waving a peanut butter sandwich at one point and a jar of peanut butter later, Harkin said he was "nothing short of outraged" at the increasing number of food-poisoning outbreaks. He said consumers should be able to rely on the safety of food staples like peanut butter found in nearly every home.

"If that's not safe, we have to ask what is," Harkin said, adding he would eat his peanut butter sandwich to show major brands found in grocery stores are not affected by the current outbreak or recall.

Harkin asked how a Texas plant owned by Peanut Corp. could have operated unlicensed and uninspected for nearly four years. The Associated Press reported this week that the company did not register with Texas health officials after it opened in March 2005 and state officials inspected it only after discovering it during the current outbreak.

"Should I be alarmed about that?" Harkin asked Sundlof. "I mean, how many plants are operating like this?

Sundlof, who didn't answer Harkin's question directly, said states have different licensing and inspection requirements.

More illnesses could be linked to the salmonella-contaminated peanut products over the next two to three weeks, although the outbreak is slowing, Assistant Surgeon General Ali Khan said.