(CNN) -- A slaughterhouse that has been accused of mistreating cows agreed Sunday to recall 143 million pounds of beef in what federal officials called the largest beef recall in U.S. history.



Officials said this is the largest recall in the United States, surpassing a 1999 recall of 35 million pounds.



Keith Williams, a U.S. Department of Agriculture  spokesman, said investigators have found no cases of illness related to the recalled meat.



But Dick Raymond, the undersecretary of agriculture for food safety, said there was a "remote probability" that the meat from the Westland/Hallmark Meat Packing Company in Chino, California, could cause illness in humans.



The amount of beef -- 143 million pounds -- is roughly enough for two hamburgers for each man, woman and child in the United States.



The largest U.S. meat recall before Sunday came in 1999, when about 35 million pounds of product possibly contaminated with listeria were ordered off shelves. USDA officials said that was Class I recall, involving a known risk to human health.



Sunday's action was a Class II recall, under which authorities say there is little risk of illness.



Raymond said cattle that had lost the ability to walk since passing pre-processing inspections were slaughtered without an inspector having examined them for chronic illness -- a practice he said violated federal regulations and had been going on for at least two years.  Watch video of cows being abused »



Federal regulations are aimed at preventing the spread of bovine spongiform encephalopathy, or BSE -- the scientific name for "mad cow" disease.



It's important to keep downed cattle out of the food supply because they also may pose a higher risk of contamination from E. coli or salmonella because the animals tend to wallow in feces and have weaker immune systems, according to AP.



Raymond said the average age of the cattle involved is 5-7 years, meaning they were likely born long after a 1997 ban on ruminant feed, and that the incidence of BSE in U.S. cattle is "extremely rare."



"We do not know how much of this product is out there at this time. We do not feel this product presents a health risk of any significance," he said. "But the product was produced in non-compliance with our regulations, so therefore we do have to take this action."



About 37 million pounds of the meat went to school lunch programs and other federal nutrition programs since October 2006, said Ron Vogel, of the USDA's Food and Nutrition Service.



The recall dates back to February 1, 2006, and Raymond said "the great majority" of the meat has probably been eaten already. USDA officials have begun tracing the products covered by the recall, he said.



"A lot of this is fresh, raw product and with ground beef, etcetera, that has a very short shelf life and refrigerator life," he said.



Most of the beef was sent to distribution centers in bulk packages. The USDA said it will work with distributors to determine how much meat remains, the AP reports.



In January, the Humane Society of the United States accused Westland/Hallmark of abusing "downed" cattle, releasing video that showed workers kicking cows, jabbing them near their eyes, ramming them with a forklift and shooting high-intensity water up their noses in an effort to force them to their feet for slaughter.



Federal inspectors halted operations at the plant earlier this month after finding "clear violations" of USDA regulations.



California prosecutors on Friday announced animal cruelty charges against two former employees of the plant.



In a statement issued February 3, Westland Meat President Steve Mendell said the company was cooperating with the USDA and called the practices depicted in the humane society video as "a serious breach of our company's policies and training."



"We have taken swift action regarding the two employees identified on the video and have already implemented aggressive measures to ensure all employees follow our humane handling policies and procedures," Mendell said. E-mail to a friend



CNN's Jen Pifer contributed to this report.
What were the animals unable to do? Who were being dragged and carried by forklifts? Ho much meat went to school lunches? Who was accused of cattle abuse? How much meat went to school cafeterias? What illness could result from consuming the beef? What did the video show? What could the beef cause in humans? What did hidden video capture? How many pounds of meat went to school lunch programs? Where did 37 million pounds of meat go?
walk cows 37 million pounds workers 37 million pounds "mad cow" disease. cows being abused illness mistreating cows 37 million school lunch programs and other federal nutrition programs
question: What were the animals unable to do?, answer: walk | question: Who were being dragged and carried by forklifts?, answer: cows | question: Ho much meat went to school lunches?, answer: 37 million pounds | question: Who was accused of cattle abuse?, answer: workers | question: How much meat went to school cafeterias?, answer: 37 million pounds | question: What illness could result from consuming the beef?, answer: "mad cow" disease. | question: What did the video show?, answer: cows being abused | question: What could the beef cause in humans?, answer: illness | question: What did hidden video capture?, answer: mistreating cows | question: How many pounds of meat went to school lunch programs?, answer: 37 million | question: Where did 37 million pounds of meat go?, answer: school lunch programs and other federal nutrition programs