State officials said on Friday to over 100 Washington state school districts that purchased beef which came from a California slaughterhouse not to serve it.

The U.S. Agriculture Department announced on Thursday that is running an investigation about the meat which came from a supplier of beef to the national school-lunch program which is said to be using meat coming from “downer” cows, that cannot walk or stand.

District spokesman David Tucker said: "We want to err on the side of caution."

The school districts in Washington receive beef from three meat processing companies.

According to Nathan Olson, spokesman for the Office of the Superintendent of Public Instruction, at least one of the three processors gets beef from Westland Meat Co, which processes carcasses from the Hallmark Meat Packing Co. slaughter house that is under investigation for violating state and federal laws that ensure food safety and are against animal cruelty.

The Humane Society of the United States released on Wednesday a video showing the workers from the California company hurting the cows and forcing them with the blades of a forklift to enter the slaughterhouse.

According to federal regulations, downer cows have to be kept out of the food supply because it can pose a risk to E.coli, salmonella contamination or mad cow disease.

Westland is known to be a supplier to a USDA program that gives beef to needy families, elderly and schools. In 2004-2005 it has supplied beef to schools in 36 states.

Schools were not told to take beef from their menus, but not to serve children beef or any kind of meat that came from a processor linked to Hallmark or Westland.

Olson said: “We've put a hold, so they can't use the beef. What they do after that is up to them."

Many schools in Washington State pulled beef off their menus.