Inspectors say they found no problems at a Chinese factory making dumplings which poisoned at least 10 people and put a girl in a coma in Japan.
Thousands of people have reported feeling ill after eating the food
A group from Japan toured the Tianyang Foods factory in Hebei province on Wednesday and reported that it was clean and well-maintained.
Japan has said the product may have been contaminated deliberately.
A senior Chinese official has said that activists opposed to improved Chinese relations with Japan could be to blame.
The case has caused huge media interest and public alarm in Japan, where dumplings are a popular product.
Ten people fell ill after eating the dumplings - thin dough parcels containing meat and vegetables - and thousands more reported feeling ill.
The product was later found to contain the highly toxic organophosphate pesticide methamidophos.
A second contaminant, dichlorvos, was also detected but is not known to have caused any sickness.
The five-year-old girl who fell ill was reported to be out of a coma and recovering.
Japan Tobacco Inc (JT), which imported the dumplings, has since recalled them and other Tianyang Foods products from sale.
Company president Hiroshi Kimura apologised "from the bottom of my heart" for causing concerns about food safety.
Media reports have criticised the company for taking a month to alert the public to initial reports of illness among consumers.
Mr Li said he would eat dumplings when he returned to Beijing
JT has also lost a proposed merger with the major Japanese company Nissin Food over the scandal.
"When food poisoning takes place, it is a universal rule that food makers should immediately take action, such as a recall," said Nissin Food president Koki Ando at a news conference confirming the decision.
"There seems to be a fundamental difference between us and JT about food safety issues."
The head of a Chinese delegation of food experts has asked the Japanese media to "trust the governments both of Japan and China and report on this with calm".
"Today is the eve of the Lunar New Year in China. More than one billion people will eat dumplings tonight," he said in a press conference at which he appeared on the verge of tears.
"I will eat dumplings myself tonight once I get back to Beijing."
China has been hit by a string of food and product safety scandals in recent years, including tainted toothpaste, contaminated pet food and high levels of lead in toys.
Beijing introduced new laws last year aimed at tightening national standards in food production.