WASHINGTON — The head of the Southern California slaughterhouse at the center of the largest beef recall in U.S. history acknowledged Wednesday that cattle were illegally slaughtered at his plant and that cows too sick to stand were forced into the food supply.

Westland/Hallmark Meat Co. President Steve Mendell made the admissions after a congressional panel forced him to watch undercover video of abuses of cattle at his plant. Mendell watched head-in-hand as cows were dragged by chains, jabbed by forklifts and shocked to get them into the box where they’d be slaughtered.

Afterward he briefly bowed his head, then backed away from claims he made in his written testimony that no ill cows from his plant entered the food supply.

Napa schools pulled beef from their menus in early February in response to the allegations that Westland/Hallmark's Chino shaughterhouse used inhumane and illegal practices on sick and injured cows.

The school district is considering adding beef back to schoolchildren menus as early as next Monday, according to district food services manager Jesse Rios, but talks are just starting about how soon to bring back beef to the schools.

So-called downer cattle are mostly barred by federal regulations from entering the food supply because they have a higher risk of infection.

The panel’s chairman, Rep. Bart Stupak, D-Mich., asked Mendell whether it was logical to conclude from the video that at least two downer cows entered the nation’s food supply.

“That would be logical, yes sir,” Mendell said.

“Has your company ever illegally slaughtered, processed, or sold a downer cow?” Stupak asked.

“I didn’t think we had sir,” Mendell said.

Reminding him that he was appearing under oath, lawmakers asked him why he claimed in written testimony that the abused cows where headed to be euthanized, not for the food supply.

“I had not seen what I saw here today,” said Mendell. He said that the Agriculture Department had refused to allow him to see some of the undercover video shot by the Humane Society of the United States.

Stupak pointed out that the video has been posted on the Humane Society Web site.

It was Mendell’s first public appearance since the undercover video led to his plant’s shutdown and last month’s recall of 143 million pounds of beef. Mendell was appearing under subpoena before the House Energy and Commerce investigative subcommittee. He was a no-show at a committee hearing last month.

Mendell noted that no illnesses have been reported from the recalled beef and the Agriculture Department has found no evidence of problems with it. Some 50 million pounds of the beef went to federal nutrition programs, mostly school lunches.

Mendell said he’s received death threats. He contended that his company has a long record of good safety procedures and was in the process of taking extensive corrective actions in response to the video when the Agriculture Department shut him down and called for a recall of product produced over the past two years.

“Our company is ruined. We cannot continue,” Mendell said. Some 220 employees have lost or are about to lose their jobs, he said.

Two workers shown on the Humane Society video were fired and are facing animal cruelty charges from San Bernardino County prosecutors in an ongoing criminal investigation. Lawmakers have criticized Agriculture Department inspection procedures and called for reform.