Large Listeriosis Outbreak Linked to Cheese Made from Pasteurized Milk, Germany, 2006–2007

Abstract

A commercial cheese (acid curd) made from pasteurized milk caused a large listeriosis outbreak in Germany from October 2006 through February 2007. The Listeria monocytogenes outbreak strain was identified in humans and in cheese samples from a patient's home and from the production plant. During the outbreak period, 189 patients were affected, which was 97% above the mean case number for the respective time period of the years 2002 to 2005. Of patients with available detailed information on cheese consumption (n = 47), 70% reported to have consumed the incriminated cheese product. Recent European food safety alerts due to Listeria-contaminated cheeses more often concerned products made from pasteurized or heat-treated milk than from raw milk. The findings should be considered in prevention guidelines addressing vulnerable populations.