Extra checks on Japan imports

Switzerland has toughened checks on food imported from Japan, amid fears of radioactive contamination from the country's nuclear disaster.

"All batches from Japan must be accompanied by a declaration from competent Japanese authorities confirming that the product has been harvested or treated before the nuclear accident of March 11," said the Swiss Federal Office of Public Health on Thursday.

Any food product that was harvested after this date from the 12 prefectures affected by the accident must undergo analysis to determine that radioactive traces are below a certain limit.

Swiss authorities added that customs will conduct checks on samples.

Several countries, including China, Taiwan, Singapore and the United States, have banned some food imports from Japan on fears of radioactive contamination.