Russia has set a deadline for this Friday for U.S. exporters to certify that their beef and pork products have been tested to confirm it is free of the common feed additive ractopamine. The new requirement may effectively halt beef and pork imports by Saturday, reports Marketwatch.

"The back and forth we've had with Russia on ractopamine has gone on for some time," said Joe Schuele, spokesman for the U.S. Meat Export Federation. "They've now reiterated they would impose the documentation requirement."

Russia's veterinary and phytosanitary surveillance service announced a zero-tolerance policy for the residue a year ago and the country barred imports from a U.S. pork producer as recently as September after residues were detected in a shipment, the group said.

In August, Russia said it would not import from 20 Brazilian pork plants because "they failed to provide adequate information about ractopamine use," according to the U.S. federation.

Through the end of September 2012, beef sales to Russia have amounted to approximately $242 million, up 25% from the same time in 2011. For pork, sales are up 14% from September 2011, at $208 million. Russia is one of the 10 largest importers of both U.S. pork and beef.

Source: Marketwatch/Wall Street Journal