Agriculture Minister Giorgios Dris said in comments published Friday that a cheese-control squad was needed to avoid further blows to the reputation of one of Greece's main exports.
"We will be merciless," Dris said, who dubbed the new unit the "feta police."
Listeria can cause serious illness in children, frail or elderly people, and those with weakened immune systems. Healthy individuals may suffer short-term symptoms such as high fever, headaches, stiffness and nausea. The infection can be especially serious among pregnant women, causing miscarriages or stillbirths.
After years of debate, the European Union late last year gave Greece the sole right to use the name feta. Denmark, a major feta producer, is fighting the decision.
Greece won its battle by claiming that feta should be made only from sheep's milk, or a mixture of goat and sheep's milk, from livestock that eat grass and flowers in the rugged Greek countryside.
Kolios, the Greek company that shipped 6,560 pounds of the listeria-tainted feta to Norway, advertised on its Internet site that it also manufactured feta from cows milk.
"This is insulting for the country, its institutions and the product," Dris was quoted as saying.
According to the American Centers for Disease Control, listeria can contaminate foods made from unpasteurized milk or can contaminate foods after processing if good manufacturing practices are not followed.
Dris said the company would be prosecuted and closed if it was found to be breaking cheese-making regulations.
Deputy Agriculture Minister Fotis Hadjimichalis said an investigation was under way to determine how the feta sent to Norway became tainted with listeria. Tests conducted on cheese stored at the factory, which was temporarily closed on July 1, found no traces of the bacteria.
According to reports, Greek health authorities were alerted by Norway about the tainted cheese on or around July 1.
Most of the shipment to Norway was destroyed, but some packages turned up in at least one store, the Norwegian Food Control Authority said. It did not say how the cheese ended up for sale or whether anyone fell ill.
"The health authority in Oslo banned sales and the importer assured them that the shipment was under control. Later, the national food authority found such cheese in a store," the authority said in a news release.
By Patrick Quinn