At least six major foodmakers ordered recalls of frozen and prepared foods believed to have been produced at the Chinese factory behind the safety crisis, company officials said.

Big household names including Ajinomoto, Glico, Katokichi and Kibun recalled more than 30 dishes effective Friday including Chinese-style stir-fries, skewered and barbecued pork, beef tongue and curries.

China - Japan's largest trading partner and second biggest supplier of imported food - has said it found no pesticide in the dumplings but pledged an investigation.

Japanese officials warned that China needed to be thorough.

China 'must exert all its efforts to make sure this will not trigger sentiment in Japan against products made in China,' Trade Minister Akira Amari said.

Chief government spokesman Nobutaka Machimura said separately: 'China should pay utmost attention and realise the importance of food safety.'

China's soaring economic growth is tied to the strength of its giant manufacturing sector, which has become the world's factory.

But China's image has been hit by increasingly frequent reports of dangerous food or other products being sold overseas ranging from tyres to toothpaste.

The scare in Japan started when Japan Tobacco Foods, part of the cigarette giant, announced on Wednesday that insecticide had been found in imported Chinese meat dumplings.

The health ministry set up a call centre Friday to respond to a flood of inquiries from consumers. A total of 175 people called to say they had stomach aches, nausea or other symptoms from the dumplings, a ministry official said.

Media reports have given different figures. Kyodo News said 498 people had told local and national authorities they felt ill after eating the Chinese dumplings.

Ten people were still sick, with five still in hospital, the health ministry official said.

A five-year-old girl in suburban Tokyo who had been in serious condition improved slightly on Friday, with doctors able to remove a ventilator, police said. -- AFP