JINAN, Nov. 15 (Xinhua) -- A packaging sample of imported frozen aquatic products tested positive for COVID-19 on Saturday in Sishui County, east China's Shandong Province, local authorities said on Sunday.

The county government of Sishui has started an emergency plan to check the cold-chain system. The cold storage where the goods were located has been closed, and all goods and vehicles involved have been sealed.

All personnel in close contact have been traced and put under quarantine. So far, all nucleic acid test results on the people involved are negative.