A Southern California meat-packing company was barred from supplying school lunch and other programs Wednesday while federal investigators look into videotapes that showed workers mistreating sick dairy cows.

Newly installed Agriculture Secretary Ed Schafer said "appropriate actions will be taken" against Hallmark Meat Packing Co. of Chino, Calif., if it violated food safety and animal cruelty laws.

Video footage showed workers kicking, shocking and otherwise abusing "downed" cows — considered too sick or injured to walk — to force them into a federally inspected slaughterhouse.

Sen. Barbara Boxer, D-Calif., sent Schafer and California Attorney General Edmund G. Brown, Jr., letters calling on them to investigate because of health concerns.

"These practices are not only inhumane, but can also cause food borne illnesses that can endanger public health," the letters said.

"Downed cattle are 58 times more likely to carry mad cow disease than other cattle. Downed cattle also are more likely to carry other food-borne illnesses like E. coli and Salmonella, which kill hundreds of Americans every year," the letters said.

"There is no immediate health risk that we are aware of," Schafer said, but until the investigation is completed, the U.S. Department of Agriculture has barred any use of meat coming from the slaughterhouse in federal food and nutrition programs.

Hallmark supplies the Westland Meat Co., which processes the carcasses. The facility is a major supplier to a USDA program that distributes beef to needy families, the elderly and to schools through the National School Lunch Program. Westland was named a USDA "supplier of the year" for 2004-2005 and has delivered beef to schools in 36 states.

The video, released Wednesday by The Humane Society of the United States after a six-week undercover investigation, workers at a California slaughterhouse repeatedly kicking cows and ramming them with the blades of a forklift as the animals squealed in pain.

It also showed plant workers jabbing in the eyes and applying electrical shocks to cows.

In one scene, the workers shoot high-intensity water sprays up the cows' noses in what The Humane Society described as a form of animal "waterboarding," or torture that simulates drowning.

USDA regulations and California law generally do not allow mistreatment of disabled animals, such as dragging them by chains or lifting them with forklifts. Federal regulations also call for keeping downed cows out of the food supply because they may 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.

In a statement, Steve Mendell, president of Westland and Hallmark, said the company immediately terminated two employees shown in the video and suspended their supervisor.

"We are shocked, saddened and sickened by what we have seen today," Mendell said. "Operations have been immediately suspended until we can meet with all of our employees and be assured these sorts of activities never again happen at our facility."

Wayne Pacelle, president and chief executive of The Humane Society, called the mistreatment of downer cows alarming to U.S. consumers because 95 percent eat meat.

"We need to know how this food is getting to the table," he said. "Even when downed animals appear otherwise healthy, they may be harboring dangerous pathogens."