WASHINGTON -- The president of the Chino meatpacking plant that triggered the largest beef recall in U.S. history admitted Wednesday that crippled cows, which are more likely to carry disease, probably entered the food supply at his company.

"Obviously my system broke down," said Steve Mendell, president of Westland/Hallmark Meat Co., once a major supplier to the school lunch program.

Mendell initially told a House oversight subcommittee that "downer" cows at his plant "were not slaughtered, ground or sold."

But after lawmakers screened a graphic undercover video that showed ailing cows being jabbed with electric prods, beaten and rolled with forklifts toward slaughter, Mendell acknowledged that the four-minute clip did indeed show that at least two cows were processed into food.

Dressed soberly in black, Mendell, of Newport Beach, was flushed but composed, apologetic and insistent that the meat at his plant was safe for consumption. He told lawmakers that he had received death threats, that his family and employees had suffered, and that his company "is ruined" and would not reopen.

"My whole life is up in smoke," he said.

After watching a video of his plant taken by an undercover investigator from the Humane Society of the United States, Mendell briefly bowed his head and shut his eyes.

"Would you consume meat from a cow slaughtered that way?" asked Rep. Janice Schakowsky (D-Ill.).

"No," Mendell said.

The hearing by a House Energy and Commerce subcommittee touched on multiple failures in the nation's food safety system, not only within Mendell's firm but also by independent auditors, the Food and Drug Administration and the U.S. Department of Agriculture's on-site investigators responsible for monitoring Westland/Hallmark.

"There is a serious problem with our food safety system," said Rep. Bart Stupak (D-Mich.), chairman of the Oversight and Investigations Subcommittee.

Stupak noted that since his subcommittee began investigating the FDA's ability to protect the nation's food supply 14 months ago there have been at least 163 recalls and health alerts tied to FDA-regulated products. Since 2007, Stupak added, there have been 67 meat recalls totaling about 180 million pounds.

Practices at the Westland/Hallmark plant led the USDA to announce the recall of 143 million pounds of meat, 50 million of which had been sent to school lunch programs. About 20 million pounds of the school-bound meat has already been consumed.

Mendell, who ignored an initial summons to appear before the committee in February, was issued a subpoena to appear Wednesday. He arrived with one of Washington's most high-profile lawyers, Asa Hutchinson, a former congressman and former member of the Bush administration whom Mendell hired Friday.

Democrats and Republicans, who have spent most of this Congress bickering with each other, ganged up on the Westland/Hallmark president.

"There's an easy way and a hard way to answer questions from this committee," Rep. John D. Dingell (D-Mich.) warned Mendell. "Either way, we'll find out what we want to know."

Rep. Joe L. Barton (R-Texas) added his own word of caution: "There's no daylight between Republicans and Democrats on this issue."

Action against Westland/Hallmark began when the Humane Society released video filmed by an investigator Jan. 30. Five on-site USDA inspectors had failed to notice anything wrong.

The plant, which slaughtered about 500 cattle a day, shut operations Feb. 4. After the Humane Society provided video evidence that downer cows were being slaughtered, Westland/Hallmark voluntarily recalled the beef Feb. 17.

Downer cows have been banned from entering the food supply since 2004, but the USDA has made an exception for cows that were inspected after they fell and seemed only to have external injuries. The Westland/Hallmark cows were not being inspected.