Japan has stopped importing beef from a U.S. facility after finding a meat shipment that may have violated the age limit of beef as agreed upon between Japan and the United States, the government said Friday.

Japan requires that the United States limit shipments to meat from cattle aged up to 20 months and remove the brains, spinal cords, bones and other risky materials in order to safeguard against mad cow disease, or bovine spongiform encephalopathy.

The facility was identified as a meatpacking plant of Tyson Fresh Meats Inc. in Lexington, Neb.