WASHINGTON — The agriculture secretary today resisted calls from Democratic senators for a complete ban on so-called downer cattle — those unable to walk — from entering the food supply.

In the wake of the largest beef recall in U.S. history, Agriculture Secretary Edward T. Schafer announced new steps to ensure the safety of the country’s meat supply, including more random inspections of slaughterhouses and immediate audits of the 23 plants that supply meat for federal programs, primarily school lunches.

But Schafer contended downer cattle could occasionally enter the food supply safely, in accordance with USDA rules, after an additional inspection by a veterinarian.

“The rules say if one goes down you call the veterinarian to make a judgment,” Schafer told a Senate hearing. “Today I’m convinced the rules in place are such where we are protecting the supply,” he said.

Schafer ran into resistance from Sen. Herb Kohl, D-Wis., chairman of the Senate Appropriations agriculture subcommittee.

“We cannot allow a single downer cow to enter our food supply under any circumstances,” Kohl insisted in his opening statement. He also urged Schafer to install cameras in slaughterhouses.

It was Schafer’s first Capitol Hill appearance since the release in late January of video — shot by the Humane Society of the United States — showing workers at Westland/Hallmark Meat Co. in Chino, Calif., shoving and kicking sick, crippled cattle, forcing them to stand by using electric prods, forklifts and water hoses.

In response, the Agriculture Department shut down the plant and on Feb. 17 ordered the recall of 143 million pounds of the company’s beef — the largest recall in U.S. history — because the company broke rules preventing the downer cattle from entering the food supply. Downers, those too sick or injured to walk, pose a higher risk of E. coli, salmonella contamination, or mad cow disease since they typically wallow in feces and their immune systems are often weak.

Westland/Hallmark was a major supplier to school lunch programs.

Two workers shown on the video have been fired and charged with animal cruelty by the district attorney in San Bernardino County, Calif. One of the workers appeared in court in California Thursday and afterward his attorney, Mario Martinez, said that his client was “just an employee making $9 an hour. He was following directions.”

The worker, Rafael Sanchez Herrera, was ordered to return for another hearing in March.

Schafer insisted his agency is taking the problem seriously and will investigate fully. He said he hadn’t yet determined whether problems like those at Westland/ Hallmark — which the Humane Society says it chose at random for an undercover investigation — existed at other plants. Schafer also tangled with Sen. Tom Harkin, D-Iowa, about whether there was actually a safety risk from the recalled beef.

Schafer contended that not all the cattle shown on the Humane Society video ended up passing veterinarian inspections and getting slaughtered. He said others had already passed inspections, and while Westland/ Hallmark violated USDA rules by not calling a veterinarian back after the cows fell down again, there was minimal safety risk.

“It is extremely unlikely that the mishandled animals pose a risk to human health,” said Schafer.

“If you are there saying absolutely that meat was OK for everyone to eat then why was it recalled?” Harkin asked. “As I understand it there was not a veterinarian called in to inspect these cattle afterward, so we don’t know” whether they were sick or not.

Harkin condemned the USDA rules that rely on slaughterhouse officials to call a veterinarian back if a cow falls down after already passing its inspection.

“I think that’s a very poor requirement,” Harkin said. “Talk abut the fox guarding the hen house. This is a classic case of it.” After the hearing Kohl said he would consider pursuing legislation to change that rule and enforce a 100 percent ban on downer cattle.

Schafer’s testimony came a day after the Humane Society sued USDA over the rule, calling it a loophole.

In 2004, the USDA tightened regulations to prohibit the slaughter of all downer cows after a case of mad cow disease was discovered in Washington state. The agency subsequently decided to allow slaughter of cows that fell down after an initial veterinarian inspection but appeared otherwise healthy and were re-inspected.

Schafer told reporters after the hearing that it was not fair to cattle owners to ban the slaughter of cows that may be perfectly safe to eat and just have a broken leg or hip.

Senators noted USDA is short about 500 inspectors from its full complement of about 8,000. Al Almanza, administrator of USDA’s Food Safety and Inspection Service, told skeptical senators that the safety service nonetheless keeps slaughter lines fully staffed by pulling people from other jobs.

The hearing came as some of the world’s largest food makers pulled products that were found to contain beef included in the recall.

General Mills Inc. said it had recalled 35,000 cases of Progresso Italian Wedding soup, while Nestle Prepared Foods Co. recalled nearly 50,000 cases of its Hot Pockets Philly Steak & Cheese and Hot Pockets Croissant Crust Philly Steak & Cheese meals.

ConAgra said it had used beef from Westland/Hallmark in several days of production of several products, including Slim Jim meat and cheese sticks, Pemmican beef jerky, Hunt’s spaghetti sauce with meat flavor, Banquet Mac & Cheese, and Manwich with beef refrigerated tubs.

ConAgra said only a tiny fraction of the listed products were affected.

— Associated Press Writers Gillian Flaccus in Los Angeles and Frederic J. Frommer contributed to this report.

On the Net:

U.S. Department of Agriculture: http://www.usda.gov

Humane Society of the United States: http://www.hsus.org

American Meat Institute animal welfare site: http://www.animalhandling.org/