Several Chinese provinces are stepping up inspections of fresh and frozen meat and seafood, including imported products, after a new outbreak of coronavirus infections linked to a Beijing food market.
The tougher checks are raising fears of possible delays in handling cargoes or even temporary halts to imports.
China is the world's top meat buyer, bringing in almost 4 million tonnes in the year to date.
Beijing has reported 79 novel coronavirus cases over the past four days, the biggest concentration of infections since February, with most linked to Xinfadi, the biggest wholesale food market in Asia.
Media reports raised concerns that produce at the market could have been contaminated with the virus, after it was found on a chopping board used to handle salmon.
Major supermarkets in cities across China removed salmon products from their shelves over the weekend, and Norwegian suppliers said on Monday imports of the fish had been halted.
Though Beijing officials said on Sunday that samples taken from food products sold at markets across the city had so far all tested negative for the virus, provinces including Guangdong, Henan, Hebei and Yunnan as well as the municipality of Tianjin all announced they would step up food safety checks.
The Guangdong Administration for Market Regulation said in a notice on its Weibo page on Sunday that nucleic acid testing should be done on key foods including fresh and frozen pork, beef, lamb, chicken and seafood, and especially imported frozen foods.
Farmers' markets, refrigerated warehouses, supermarkets and catering services should all be inspected, it said.
An industry source said Tianjin had begun doing Covid-19 tests on meat imports arriving at port but it was not clear what portion of cargoes were being checked.
Tianjin customs could not be reached for comment.
The stricter checks could make buyers nervous about purchasing goods from abroad. A manager with a poultry importer said he was worried that the government could suspend imports in the short-term.
Checks on frozen meat are pushing up the price of live pigs, as the inspections could increase demand for fresh meat, a Henan-based trader said.