A team of senior Chinese police officers went to Japan last Wednesday to assist with the investigation into the alleged poisoning of Chinese-made dumplings there.

And on February 15, the State Council Information Office and the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ), China's food safety watchdog, held a joint press conference to release the latest developments in the case.

These are the most recent Chinese responses to take place since Japanese media reported the case on January 30.

At least 10 people in Japan's Hyogo and Chiba prefectures reported stomachaches, vomiting or diarrhea after eating the dumplings.

The Japanese government examined the vomit of the poisoned people as well as the food packages at their houses, and found enough methamidophos, a pesticide, to poison humans. The investigation by Japanese police also found traces of the chemical on the dumpling packaging.

During the first week of this month, Chinese investigators inspected the manufacturer, Tianying Food Plant, in Hebei Province, but found nothing irregular. Nor did they find any problems related to the purchase of raw materials or the production process.

On February 13, a senior AQSIQ official said the dumplings involved in the food poisoning incident were "an isolated case", rather than the result of a general food safety problem.