But the European Union said there were no current health risks to the region’s consumers as the bloc imported little food from Japan. It confirmed that control measures would be stepped up in the wake of the disaster that seriously damaged a Japanese nuclear reactor triggering a radiation leak.
Peter Cordingley, Manila-based spokesman for WHO's regional office for the Western Pacific, told Reuters: "Quite clearly it's a serious situation. It's a lot more serious than anybody thought in the early days when we thought that this kind of problem can be limited to 20 to 30 kilometres.”
The WHO spokesman said there was no current evidence to suggest that contaminated food had been exported to other countries although "it's safe to suppose that some contaminated produce got out of the contamination zone," he said.
Leafy green vegetables, meat, milk and eggs are likely to be most at risk from contamination, said the WHO in guidance released today. However, canned food was less likely to be affected because of food processor control mechanisms.
Regional anxieties surfaced last week as reports emerged of contaminated vegetables, milk, water and dust from Japan in the aftermath of the huge quake and subsequent tsunami that is believed to have killed tens of thousands and smashed the Daiichi nuclear reactor in Fukushima.
Japan has forbidden the sale of raw milk from Fukushima prefecture and spinach from another nearby area. It said more restrictions on food may be announced later on Monday. Government officials admitted that some food with radioactivity above the safety limit might be on shop shelves in Japan.
Last week, the European Commission said there were currently no health risks to consumers as Japan was authorised to export few food products of animal origin into the region – including some vegetables, bivalve molluscs, feed and feed derivatives.
The EC representative reassured a meeting of the Council of Ministers that “following the possible radioactive contamination of the products, controls will be reinforced by the Member States importing such products”.
The Geneva-based body today issued more detailed guidance on the possible risk of food contamination from radiation.
A number of compounds are of particular concern for food contamination - including isotopes of strontium, isotopes of iodine - particularly iodine 131, and isotopes of caesium, notably caesium 137.
Leafy greens will be most exposed to direct contact from contaminated air, it added. Meat, milk and egg products will be at risk of contamination through the animal eating contaminated grass or feed.
Processed products such as canned foods are unlikely to contain potentially contaminated raw material because of the existing safety and quality screening mechanisms already in place in the food industry.