Outbreak of listeriosis caused by infected beef meat from a meals-on-wheels delivery in Denmark 2009

An outbreak of listeriosis in Denmark occurred in May 2009. Multilocus variable number of tandem repeats analysis typing, later confirmed by pulsed-field gel electrophoresis typing, showed that isolates from eight patients had identical patterns and were distinguishable from Listeria monocytogenes isolates from other Danish patients. Seven out of eight patients had received a meal with beef from the same meals-on-wheels delivery catering company 3 weeks prior to onset of disease. Two patients died of their infection. Large-scale delivery of precooked meals to a vulnerable population represents a threat if proper measures against listeriosis are not taken.