* China, S. Korea toughen checks on Japanese food
* More cases of contaminated food seen -- expert
* Asian consumers worry about safety of Japanese foods
(Adds Chinese Foreign Minister in paragraph 3)
By Sui-Lee Wee
BEIJING, March 21 (Reuters) - China and South Korea announced on Monday they will toughen checks of Japanese food for radioactivity, hours after the World Health Organisation said the detection of radiation in some food in Japan was a more serious problem than it had expected.
China will monitor food imported from Japan for signs of radiation, state news agency Xinhua reported, citing the national quality watchdog, while South Korea will widen radiation inspections to dried agricultural and processed food from fresh agricultural produce.
"Japan's nuclear leak has sounded an alarm bell for the international community about the safety of nuclear energy," Chinese Foreign Minister Yang Jiechi said in a speech on Monday, a transcript of which was posted on his ministry's website (www.mfa.gov.cn).
The WHO said it had no evidence of contaminated food spreading internationally, but officials in Japan's Ibaraki and Fukushima prefectures, the areas closest to the earthquake-damaged Daiichi nuclear plant, found higher than usual levels of iodine in samples of spinach and milk.
"Quite clearly it's a serious situation," Peter Cordingley, Manila-based spokesman for WHO's regional office for the Western Pacific, told Reuters in a telephone interview on Monday.
"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," he said.
There is no evidence of contaminated food from Fukushima prefecture, where the plant is located, reaching other countries, he said.
"We can't make any link between Daiichi and the export market. But it's safe to suppose that some contaminated produce got out of the contamination zone," he said.
He warned that it was difficult to know whether the radioactive material found in some food in Japan originated from the stricken Daiichi plant.
The WHO was in touch with Japan's health ministry, and WHO experts at its Geneva headquarters would be able to give more guidance later on Monday, Cordingley said.
There could be more cases of contamination within Japan, added Peter Ben Embarek, a Beijing-based WHO food safety expert, though said he was not concerned about the contaminated foods reaching other countries.
"There is no sign that a lot of Japanese contaminated food products will find its way into the international market because of the current efforts to monitor what's going on there," he told Reuters.
Japan's government has halted shipment of raw milk from Fukushima prefecture, and told a total of four prefectures near the stricken plant to hold shipments of spinach.
Leafy green vegetables, and milk, egg and meat products are the biggest concern for possible contamination, the WHO said.
Eating food containing radioactive materials could increase the risks of certain cancers in the future, Ben Embarek said.
If radioactive iodine is ingested, it can accumulate in and cause damage to the thyroid, Ben Embarek said.
He said while he saw no risk in people outside Japan eating Japanese food, those in Japan should avoid eating fresh food produced in and around the nuclear plants.
Japan is a net importer of food, but it has substantial exports of fruits, vegetables, dairy products and seafood, of which the country exports around 200,000 tonnes per annum, according to the WHO.
The main markets for Japanese food products are Hong Kong, the United States and China, the WHO said.
Taiwan's Atomic Energy Council found a small amount of radiation on a shipment of broad beans from southern Japan during its inspections of imports over the weekend, but the level detected was within limits. The beans will be destroyed.
In Hong Kong, some luxury hotels including the Shangri-La hotel chain and Four Seasons Hotel have suspended imports of fresh food from Japan as a precautionary measure.
Malaysia's largest sushi restaurant chain said on Monday it had stopped importing raw food from Japan over fears of radiation contamination, and a New Delhi based supplier to five-star restaurants had also stopped imports of Japanese foods.
"Customers are worried and they keep calling us, but what can we do? All we can say is we don't know when we can resume sales," said Vinod Kumar, director of Rahul Trading Corp.
But in China, where unfounded rumours of impending nuclear contamination prompted a run on salt last week in the belief it could protect from radiation, at least one shopper at an upmarket store specialising in Japanese food dismissed fears.
"Radiation? There is nothing to be afraid of. Anyway, Japanese rice tastes good," said a middle-aged man who would not give his name.
(Additional reporting by Ben Blanchard and Michael Martina in Beijing, Clare Jim and Jonathan Standing in Taipei, Angie Teo and Razak Ahmad in Kuala Lumpur, and C.J. Kuncheria in New Delhi; Editing by Daniel Magnowski)
Created by Daniel Magnowski