Washington sharply criticized Moscow Monday for banning imports of US meat, saying the Russians had ignored scientific proof that an additive in US animal feed is safe.
Top US officials said that global food-safety experts had cleared the additive, ractopamine, as safe at levels used in the United States.
But Russia, enforcing its own rules against any presence of ractopamine, on Monday banned all imports of beef, turkey, chicken, pork and other animals
"The United States is very disappointed that Russia has taken action to suspend all imports of US meat, which is produced to the highest safety standards in the world," said US Trade Representative Ron Kirk and US Agriculture Secretary Tom Vilsack in a joint statement.
"Russia has disregarded the extensive and expert scientific studies conducted by the international food safety standards body, the Codex Alimentarius Commission," they said.
The commission "has repeatedly concluded that animal feed containing the additive ractopamine is completely safe for livestock and for humans that consume their meat."
They said Moscow had ignored repeated requests for talks on the issue "and instead has simply suspended US meat imports."
The United States exported $557.7 million worth of fresh meat, chilled or frozen, to Russia last year, according to US data.