Multistate Outbreak of Salmonella Serovar Muenchen Infections Associated with Alfalfa Sprouts Grown From Seeds Pretreated with Calcium

Multistate Outbreak of Salmonella Serovar Muenchen Infections Associated with Alfalfa Sprouts Grown from Seeds Pretreated with Calcium Hypochlorite

Journal of Clinical Microbiology, October 2001, p. 3461-3465, Vol. 39, No. 10
0095-1137/01/$04.00+0   DOI: 10.1128/JCM.39.10.3461-3465.2001Mary E. Proctor,1,* Marge Hamacher,2 Mary Lou Tortorello,3 John R. Archer,1 and Jeffrey P. Davis1

Bureau of Communicable Diseases, Division of Public Health, Wisconsin Department of Health and Family Services, Madison, Wisconsin 537011; Wisconsin State Laboratory of Hygiene, University of Wisconsin-Madison, Madison, Wisconsin 537062; and National Center for Food Safety and Technology, U.S. Food and Drug Administration, Summit-Argo, Illinois 605013

Received 7 May 2001/Returned for modification 9 July 2001/Accepted 22 July 2001


During September 1999, a multistate outbreak of Salmonella serovar Muenchen infection associated with eating raw alfalfa sprouts was identified in Wisconsin. Despite use of a calcium hypochlorite sanitizing procedure to pretreat seeds before sprouting, at least 157 outbreak-related illnesses were identified in seven stateshaving sprouters who received alfalfa seed from a specific lot. The continued occurrence of sprout-related outbreaks despite presprouting disinfection supports the concern that no available treatment will eliminate pathogens from seeds before sprouting and reinforces the need for additional safeguards to protect the public. A lack of consumer knowledge regarding exposure to sprouts documentedin this investigation suggests that more-targeted outreach to high-risk individuals may be needed to reduce their risk.