Many Japanese citizens around the Fukushima nuclear plant have evacuated amid growing fears of increased radiation seeping into the ground and air.
But Japan officials now fear that high levels of radioactive materials have entered the food supply as efforts continue to get the damaged nuclear reactors under control.
Indeed, Japan has placed restrictions on foods, including spinach and milk, that were produced in two provinces around the Fukushima Daiichi nuclear plant. Food inspectors detected iodine and cesium in the food, two of the more dangerous radioactive byproducts that are feared to have been released from the plants in Fukushima.
Spinach from one farm in Hitachi, a town 45 miles away from the plant, contained 27 times the amount of iodine and four times the amount of cesium that is considered safe.
At a dairy farm in Iitate, which is about 18 miles from the plant, the raw milk contained iodine levels 17 times higher than considered safe.
Radioactive iodine found in the air falls to the ground naturally, or is brought down with the rain or snow. On a farm, the radioactive substances can embed in the grass that cows eat, and are then excreted in its milk.
High levels of iodine that can be absorbed through the milk can accumulate in the thyroid and specifically cause thyroid cancer. High levels of cesium can damage cells and put many people at higher risk of developing other kinds of cancer.
Many of the local farms surrounding the plant export their products to areas outside the radiation zone. Some products are even shipped internationally to countries such as the United States. Top imports include snack foods, scallops, wine and beer, processed fruit and vegetables, herbal tea, vegetable oils, coffee.
While none of the produce found to be contaminated has been shipped outside of the local Japanese market, officials said, there might have been some contaminated produce that was not tested and could have slipped through. Many food-safety experts say that consuming food or milk that contains high radiation levels can be as dangerous as exposure to high levels in the air.
But experts say there's no need to boycott the sushi or other seafood delicacies just yet. Less than 4 percent of food is imported to the United States from Japan, including processed and snack foods. About 2 percent of seafood the United States consumes comes from Japan, according to the U.S. Department of Agriculture. Scallops is the largest seafood import to the U.S. In 2010, nearly $64 million worth and 3,300 metric tons of scallops were imported from Japan.
The largest percieved danger may be around raw seafood that is used to make sushi. Tuna is the second largest seafood import from Japan, with nearly 350 metric tons and nearly $4 million worth of imports, according to the U.S. Department of Agriculture. However, tuna imports are considered small relative to the scallop imports as well as the overall percentage of seafood imports to the U.S.
Also, radiation levels become diluted in larger bodies of water, so seafood caught from the ocean should have only trace amounts of radiation, if any.
Since 9/11, U.S. Customs and Border Protection and the U.S. Department of Agriculture have implemented blanket radiation screenings for nearly all U.S. imports, including food.
And U.S. food-safety officials say they're confident in the system designed to prevent contaminated foods from entering from Japan.