UPDATE 1-Russia bans U.S meat over feed additive from Feb. 11

* Russia bans imports of U.S. beef and pork

* Russia wants imports certified free of ractopamine

MOSCOW/LOS ANGELES, Feb 1 (Reuters) - Russia has decided to ban imports of U.S. beef and pork due to the feed additive ractopamine, which they may contain, Russia's Veterinary and Phyto-Sanitary Surveillance Service (VPSS) said in a statement.

Russia got 7.5 percent of its imported beef and 11.4 percent of its imported pork from the United States between January and September 2012.

The service would impose a temporary ban on U.S. beef and pork starting on Feb. 11, it added in the statement.

Ractopamine is a growth stimulant used to make meat leaner and which is banned in some countries because of concerns that residues could remain in the meat and cause health problems, despite scientific evidence it is safe.

"We're acutely aware of the fact that Russia and the U.S. have hit an impasse" over ractopamine, Tyson Food Inc Chief Executive Donnie Smith said on a media call on Friday.

Smith declined to say how the ban could affect business at Tyson, the largest U.S. meat company.

In Tyson's fiscal 2012 (Oct-Sept), Russia accounted for 9 percent of the company's $1.1 billion in international pork sales. The company's latest fact book did not have a figure for its beef sales to Russia.

Russia imported 1.25 million tonnes of red meat, excluding offal, worth $4.47 billion from non-CIS countries in 2011, according to official customs data.