Published: Nov 16, 2012 2:27 PM EST
Updated: Nov 17, 2012 7:31 AM EST

FRESNO, California (AP) - The Humane Society of the United States said Friday a landmark $500 million settlement has been reached in a slaughterhouse abuse case that led to the biggest meat recall in the country's history.

The federal civil court settlement is the largest-ever penalty for an animal abuse case.

The now defunct California company Westland/Hallmark Meat Co. was a supplier of meats for the national school lunch program when an undercover video showed "downer cows" - those too weak or sick to walk - being dragged with chains, prodded with forklifts and sprayed with high-pressure water by employees who wanted them to stand and walk to slaughter.

Downed cows can pose an increased risk for mad cow and other diseases. Thus far, no mad cow cases have been linked to the recalled meat.

The humane society sued for fraud, and the U.S. Justice Department intervened because federal contracts required that animals be treated humanely.

Attorneys for the defendants and the Justice Department did not immediately return calls seeking comment.

The settlement is largely symbolic because the company is bankrupt.

"It's a deterrence judgment," said Jonathan R. Lovvorn, chief counsel for animal protection litigation at the humane society. "It informs other federal government contractors that when your contract says you provide humane handling, if you don't do that you're likely to end up bankrupt as well."

He added, "When you look at the video, it's about as far from humane treatment as you can get."

In the court papers, the plaintiffs alleged that the meatpacking plant slaughtered and processed "downer" cows from January 2004 to September 2007 at the average rate of one every six weeks.