World Bulletin/News Desk

An outbreak of listeria tied to contaminated Danish meat has killed 12 people since September last year, with most of the deaths coming in the past three months, Danish health authorities said on Tuesday.

The Ministry of Food, Agriculture and Fisheries said the source of the outbreak was finally traced on Monday to a popular type of cold cut called Rullepolse, which means rolled sausage in Danish, produced by a food manufacturer near Copenhagen.

Listeria can lead to fatal infections especially in young children, the elderly and those with weakened immune systems. Infection can have particularly harmful effects for pregnant women, including miscarriage and stillbirths.

The State Serum Institute (SSI), an infectious disease research institute under the Danish health ministry, said 20 people had been infected since September 2013, with 15 of those cases recorded since June.

It said 12 people had died in the outbreak -- the first on Sept. 13 and the latest just a few days ago on Aug. 9.

The government only asked SSI to investigate a possible outbreak on June 26 and it took more than a month to find the source -- manufacturer Jørn A. Rullepølser A/S in Hedehusene, 30 km (20 miles) west of Copenhagen.

"We found out last night, when we were contacted by the Food Administration, who immediately ordered that all production and sales be stopped," company official Christina Lowies Jensen told television news station TV2.

"This is completely incomprehensible for us. It is a very complex case and we don't understand what went wrong," she said.

The highly popular Rullepolse is typically made of flattened pork belly stuffed with spices and herbs, which is then rolled up and sliced as a cold cut.