The US has notified its trading partners that US beef is safe to eat and urged countries to resume imports of US beef.

The US Department of Agriculture’s chief veterinarian, Ron DeHaven, wrote to his counterparts abroad detailing what the US has done to protect the safety of its beef and search for other cases of BSE, or mad cow disease, reported the Associated Press.

“This information demonstrates that any remaining trade restrictions against US beef and beef products can be lifted without compromising safety,” DeHaven was quoted by AP as saying.

About 50 countries banned imports of US beef or cattle after a case of BSE was found in Washington state in December. Some countries have already eased restrictions on US beef, but some, including major US beef buyer Japan, still have full bans in place.

Japan has said it will not lift its ban until the US commits to testing 100% of its cattle for BSE. The USDA has said it will increase its testing to at least 220,000 cattle per year, compared to the current target of 40,000 per year, but sees 100% testing as unnecessary.