Customers who purchased the items will be called by CostCo to notify them of the recall, Wilson said. The calls will be followed up with a letter.
Wilson said Costco's independent testing of the smoked salmon hasn't yet turned up any positive results for salmonella. He said the company has not received any reports of illnesses.
In the Netherlands Foppen estimated the number of infections could rise.
Since the company set up a public information phone line two days ago, de Vries said about 1,400 people had called and around 350 of the callers "reported symptoms consistent with a salmonella infection."
Those infected by the salmonella bacteria can suffer symptoms including fever, vomiting and diarrhea.
Foppen, which processes fish in the Netherlands and at a factory in Greece, is investigating the cause of the outbreak.
"The investigation into the cause is under way and has been narrowed down to one production line at one factory (in Greece)," De Vries said. "We can't yet say what the cause of the infection was."
Foppen has halted all production of smoked salmon until the investigation is completed, he added.