The FDA said those foods will be detained at entry and will not be sold to the public. The agency previously said it would just step up screening of those foods.
Other foods imported from Japan, including seafood, still will be sold to the public but screened first for radiation.
Japan's Fukushima Dai-ichi nuclear complex has been leaking radiation after it was damaged in a devastating earthquake and tsunami earlier this month. The sea near the nuclear plant has also shown elevated levels of radioactive iodine and cesium, prompting the government to test seafood.
Japanese foods make up less than 4 percent of all U.S. imports, and the FDA said it expects no risk to the U.S. food supply from radiation. Officials and health experts say the doses are low and not a threat to human health unless the tainted products are consumed in abnormally excessive quantities.
Still, the World Health Organization said this week that Japan should act quickly to ensure that no contaminated foods are sold. The most common imports from Japan to the United States are seafood, snack foods, and processed fruits and vegetables.
Rep. Rosa DeLauro of Connecticut, the top Democrat on the House subcommittee that controls FDA spending, wrote agency officials Tuesday questioning how they could say with certainty that there is no threat to the U.S. food supply from Japanese radiation. She noted that the FDA is not always able to track where food production facilities are located in other countries.
Food safety advocates long have expressed concern over the agency's lack of money for reliable inspections abroad. A food safety overhaul bill signed into law by President Barack Obama earlier this year would increase inspections of foreign food facilities that export to the United States.
David Acheson, a former FDA associate commissioner of foods, acknowledged concerns about the safety of imported foods and the lack of agency resources. But he said the agency prioritizes risky situations like the one in Japan.
"Whenever there is a threat, then resources appear," he said.