In this Aug 7, 2018 file photo, shrimp are displayed for sale inside a Vanguard hypermarket, operated by China Resources Enterprise Ltd., in Shanghai, China, on Aug 7, 2018. (QILAI SHEN / BLOOMBERG)

BEIJING - China's customs authorities said Friday that it has decided to halt imports from three Ecuadorian shrimp producers after sample inspections showed coronavirus contamination in recent shipments.

To block the transmission of COVID-19 through imported cold-chain foods, China intensified inspection and coronavirus testing of imported foods in the cold chain

One sample, collected from the inner wall of a container carrying frozen white shrimp from Industrial Pesquera Santa Priscila S.A., and product outer packing samples of both Empacreci S.A. and Empacadora Del Pacifico Sociedad Anonima Edpacif S.A. tested positive for the coronavirus on July 3, said Bi Kexin, head of the import and export food safety bureau of the General Administration of Customs.

ALSO READ: There is something about meat, seafood markets that needs prompt attention

Samples of the three firms' shrimp products and inner packing all tested negative for the virus, Bi said at a press conference.  

The temporary import ban became effective starting Friday. 

The customs also ordered frozen shrimps produced by the three companies after March 12 to be returned or destroyed.

To block the transmission of COVID-19 through imported cold-chain foods, China intensified inspection and coronavirus testing of imported foods in the cold chain. As of Thursday, the country's customs officers had tested 227,934 samples concerning imported cold-chain foods. 

READ MORE: Eight GM plant species pass safety tests for import