Japan is to place stricter limits on the amount of radiation in vegetables sold for human consumption from April 1.
The new maximum limits of radioactive cesium will be between one-twentieth and one quarter of the provisional limits imposed after the Fukushima Dai-Ichi nuclear plant was crippled by the Great East Japan Earthquake and the gigantic tsunami that it triggered on March 11 last year.
Under the revised regulations, the upper limit on foods such as meat, vegetables and fish will be set at 100 becquerels per kilogram. The limit will be 50 becquerels per kg for milk and infant food and a maximum of 10 becquerels for drinking water.
At present, the levels are set at 500 becquerels per kg for the majority of foodstuffs and 200 becquerels for milk, dairy produce and water. There is presently no specific figure for infant food.
The new limits set by the Ministry of Health, Labour and Welfare are a balancing act between food producers, who have argued they are too stringent and will destroy their businesses, and citizens' groups that are demanding even tighter controls on the food that is eaten in Japan.
Many consumers -- particularly those raising young children -- say they are confused by the changing regulations and are being careful about what they purchase.
"If there really is a danger, then they should have set these limits a long time ago," said Kanako Hosomura, a housewife from Kanagawa Prefecture with two children.
"Whenever I go to the supermarket, I always look at the labels on the produce to see where it is from," she said. Vegetables, fruit and meat from the southern main island of Kyushu is considered safe, along with items from all of Shikoku and Hokkaido and most of the main island of Honshu.
The biggest concerns revolve around the prefectures north of Tokyo, in particular Fukushima Prefecture.
In a report issued this week, France's Institute for Radiological Protection and Nuclear Safety reported that while contamination levels in areas around the plant have fallen significantly since the accident, the impact will be "chronic and lasting" for many years.
Didier Champion, crisis manager at IRSN, told reporters on February 29 that Japan must maintain vigilant monitoring of fruit, milk, mushrooms, game and fish.
"There are risks of chronic exposure at low dosage, and without care this can build up over time," he said.
IRSN estimates that 408 peta-becquerels of radioactive iodine were emitted into the atmosphere after the explosions at the plant, although releases of cesium-137 were of greater concern as the element takes around 30 years to decay to half its level of radioactivity.
On Friday, the Japan Dairy Industry Association announced that its 116 member companies have detected no cesium during tests on 131 milk products, while on Thursday the Ministry of Agriculture gave farmers permission to plant rice in municipalities where cesium in last year's harvest was between 100 becquerels and 500 becquerels per kilogramme. All crops from the affected areas will have to be tested for safety before they are put on the market in the autumn.
The Japanese government is attempting to reassure its trading partners that Japanese food is safe and a number of countries, including Canada and Malaysia, have relaxed controls on imports, although they are still monitoring the situation.
On February 24, the European Union announced that it was "reinforcing controls" on imports of food and feed from 12 prefectures in Japan. The EU is requiring that all produce from the affected areas be tested before being shipped out of Japan and says it will be subject to random testing within the EU.