The United Nations organization initially said the food safety situation was "more serious" than originally thought. But spokesman Peter Cordingley said on March 21 that the assessment was based not on the levels of contamination but on the fact that radioactivity was found in food beyond the 30-kilometer (18.6-mile) evacuation zone.

On Monday, authorities in the village of Iitake urged residents to avoid drinking tap water that tests showed contained more than three times the maximum standard of radioactive iodine. The day before, a government ban on the sale of raw milk from Fukushima Prefecture and spinach from neighboring Ibaraki Prefecture became public.

The government has also banned sales of spinach and milk from parts of Gunma and Tochigi Prefectures, according to the prime minister's office.

Japanese officials reported levels of radioactive iodine in milk from four locations in Fukushima that ranged from about 20 percent over the acceptable limit to more than 17 times that limit. Testing at one location also found levels of cesium about 5 percent over the acceptable limit, the health ministry reported on Sunday.

In Ibaraki, a major centre of vegetable production, tests at 10 locations found iodine levels in spinach that ranged from 5 percent over acceptable limits to more than 27 times that ceiling. At seven sites, levels of cesium grew from just above 4 percent to nearly four times the limit.

Japanese Chief Cabinet Secretary Yukio Edano stressed that he believed the levels of radiation in food - while above the legal standards - do not pose any immediate health risk, saying they were mostly dangerous only if consumed repeatedly over one's lifetime.

The government will provide compensation for revenue lost by the restrictions, Edano said.