In the past two weeks, Tianyang Food Plant, in north China's Hebei Province, has undergone numerous investigations from both Chinese and Japanese authorities concerning the "dumplings poisoning case." No problems, however, have ever been found in the food processing.

The plant has suspended operation since Jan. 30 when the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ), China's quality watchdog, made a public announcement to investigate the food poisoning case.

The investigation started hours after it learned from the Japanese authorities that at least 10 people in the Hyogo and Chiba prefectures had become sick since December after eating dumplings produced by Tianyang Food Plant.

After thorough inspection, both investigators and the media said the factory was clean and tidy, and they found nothing abnormal.

Tianyang Food Plant is a state-owned enterprise with a 10-year history of exporting food products. It sent 3,970 tons of dumplings to Japan last year.

"We have strict control on production and quality," said Di Menglu, head of Tianyang. "Workers wear work clothes that cover them from top to toe and they have to pass through two checkpoints before entering the production area."

Hebei Entry-Exit Inspection and Quarantine Bureau carried out a routine sanitary checkup on the plant every six months. "Based on our records, we have never found problems in raw materials and processed food in the plant," said Cheng Fang, the bureau director.

China's exported food and other products have been under foreign criticism since early last year, from wheat gluten to toothpaste to toys and tires. Many countries and regions implemented bans, which brought great losses to Chinese export enterprises.

China-made food has been exported to more than 200 countries and regions, and 99 percent of the products are up to standard, according to the white paper -- "China's food quality and safety" -- published by the State Council, China's Cabinet, last year.

Since last year, China has stepped up efforts to enforce surveillance over food safety. A special leading group office was set up by the State Council in July to deal with matters concerning product quality or food safety.

In August, a nationwide crackdown on substandard products was carried out and lasted four months.

The government also launched a system of "red" and "black" lists of enterprises and posted the results on the Internet. Those deemed "black" were forbidden to sell or export products.

According to the statistics by the Japanese authorities, the acceptance rate of the exported food to the country in 2006 was 99.42 percent. The acceptance rate of food Japan imported from the European Union and the United States was 99.38 percent and 98.69 percent respectively.

Despite the poisoning case in Japan, citizens in the Republic of Korea still prefer food imported from China during their traditional Lunar New Year. A Korea Times article recently stated that "Though the dumplings poisoning case is still under criticism in Japan and many other countries, the Korean traditional festival can not do without China's food."

Some Japanese media also called on the public to keep calm and refrain from being oversensitive about the poisoning case.