SIMIC

It usually take three days, now it takes nine or 10, said an official with Bojun Supply Chain Co, which provides buyers with customs clearance services on foods including frozen products.

The testing, coupled with large arrivals of cold storage food, have resulted in congestion at some ports, Li Xingqian, a commerce ministry official told reporters. Still, the ministry wants to mitigate any impact on trade, he said.

About 227,934 samples have been taken from cold-storage food products by China customs, of which six tested positive for the virus, officials said. Domestically, nearly 60,000 food samples have tested negative, they said.

"It is definitely taking a longer time to clear customs," said Lin Guofa, a senior analyst at Bric Agriculture Group, a Beijing-based consulting firm. "Buyers are not so willing to import any more due to potential risks while exporters may choose not to export because of the strict testing."