The joint inspection team examined the production lines of the Tianyang Food Processing Co plant outside the provincial capital of Shijiazhuang on Tuesday.

Frozen dumplings produced at the plant have been blamed for sickening at least 10 people in Japan. Japanese investigators have found traces of the highly toxic pesticide methamidophos on Tianyang packaging.

During the plant tour, no abnormalities were found, Xinhua said, citing Japanese and Chinese inspectors.

An executive in Tianyang's director's office, who refused to give his name, confirmed the inspectors' visit and the Xinhua account, but declined to provide additional details.

A Japanese Embassy spokesman was unavailable for comment because of the Lunar New Year holiday.

The tainted dumplings case has touched off a food-safety scare in Japan, a key export market, and set back Beijing's efforts to shore up foreign consumer confidence in Chinese exports after a series of food and product safety scandals last year.

The findings of methamidophos, if ultimately traced back to Tianyang or other Chinese sources, point to Beijing's persisting troubles in enforcing its own regulations. For a decade, the government has been trying to restrict the use of methamidophos, and in 2004 banned its use on fruit and vegetable crops.

The pesticide is known to be so deadly that farmers drink it to commit suicide. -- AP

Read Japan finds 2nd type of pesticide in Chinese dumplings