An outbreak of swine flu has prompted several countries to ban imports of pork.
International trade rules allow countries to restrict or ban imports for health and safety reasons - but this has to be based on scientific evidence. The World Health Organization says swine flu does not spread by eating infected pork.
Swine flu has killed 149 people in Mexico. Cases are reported in the United States and Europe.
Consequently, China, Ukraine, Kazakhstan, the Philippines, Thailand and the United Arab Emirates have banned meat and pork products from some parts of the United States.
Russia has banned imports of all meat not treated thermally from Mexico, Texas, California and Kansas, and raw pork imports from eight other US states, Central America and the Caribbean.
China has also banned imports of live pigs and pork products from Mexico, Texas, California and Kansas.