Eggs from the same batch have also been sold in Sollentuna, Botkyrka and Stockholm, according to the National Food Administration (Livsmedelverket).
The administration believes that those infected in the eastern town may have fallen ill after eating mayonnaise made with the Polish eggs.
As salmonella is common in Poland, a special certificate is needed when importing eggs to Sweden to prove that a particular batch is not infected with the bacteria. According to food administration inspector Pontus Elvingsson, tests are generally carried that include “shit samples from the flock”.
But the certificates obtained by wholesalers at Årstahallarna in Stockholm contained information that was false.
Although health boards in Gävle and Stockholm have both begun looking into the matter, experts believe it will be hard to detect which wholesaler missed the error.
“There have been three or four operators mentioned, but they trade eggs among themselves in the halls, which makes them difficult to trace. But they are obliged to check these things; that’s what a wholesaler is supposed to able to do,” said Pontus Elvingsson.
“I hope the case is investigated properly and those responsible are held accountable,” he added.