Listeriosis from butter in Finland

Abstract

Twenty-five cases of listeriosis were reported between June 1998 and April 1999 in Finland, caused by Listeria monocytogenes serotype 3a. Six deaths were reported. Epidemiological and microbiological investigations identified the source of infection as butter. On February 19, 1999, the dairy plant involved voluntarily recalled the small packages of butter from the market, when the connection between the brand of butter and the human cases was established. The investigation found that the contaminated packages had been sold to 11 hospitals and to the retail market for many months. It is worth considering if this outbreak would have been detected had the butter not been sold to hospitals or, in the case of one hospital, given abundantly to patients in certain wards. Adequate resources and proper risk communication should be a priority in situations where many different authorities and laboratories, both at a local and national level, are involved together with industry and the media.