Temporally distinct Escherichia coli 0157 outbreaks associated with alfalfa sprouts linked to a common seed source--Colorado and Minnesota, 2003.
Epidemiol Infect. 2005 Jun;133(3):439-47
Ferguson DD, Scheftel J, Cronquist A, Smith K, Woo-Ming A, Anderson E, Knutsen J, De AK, Gershman K.
Epidemic Intelligence Service, Colorado Department of Public Health and Environment, Denver, CO 80246, USA. dayna.ferguson@state.co.us

Escherichia coli O157 outbreaks were identified in Minnesota in February 2003 involving seven persons and in Colorado in July 2003 involving 13 persons. Case isolates from the two states had matching pulsed-field gel electrophoresis (PFGE) patterns. Independent case-control studies linked infections in each outbreak with eating alfalfa sprouts that were traced to the same seed distributor. The Colorado sprouter reportedly complied with the Food and Drug Administration (FDA) sprout guidance, whereas the Minnesota sprouter did not. These investigations revealed that increased compliance with existing FDA guidance is needed and that additional research is needed to improve the alfalfa seed decontamination process. This reaffirms the FDA recommendation that raw alfalfa sprouts should be considered potentially contaminated and avoided by persons at high-risk such as the elderly, young children, and immunocompromised persons. PFGE played an essential role in linking these two temporally and geographically distinct E. coli O157 outbreaks.

From SproutNet:  Other articles related to those outbreaks: 

"E. coli 0157 NM Summary"  Georgia Department of Human Resources, Division of Public Health, Stuart T. Brown, M.D., Director

"An Outbreak of Escherichia coli O157:Nonmotile Associated with Alfalfa Sprouts - Colorado, July 2003" DD Ferguson, MD, A Cronquist, MPH, J Scheftel, DVM, MPH, A Woo-Ming, K Gershman, MD, MPH, J Knutsen, AK De, PhD

"Escherichia coli 0157 Infection and Hemolytic Uremit Syndrome (HUS), 2003" Minnesota Department of Health, Disease Control Newsletter

“Outbreak of Escherichia coli O157:NM Associated Alfalfa Sprout Consumption Colorado, 2003" Dayna Ferguson, MD, CDC Epidemic Intelligence Service Officer, CDPHE

"E. coli O157:H7 Infections Associated with Alfalfa Sprouts January (2003) ~ Hennepin and Ramsey Counties" Minnesota Department of Health 2003 Gastroenteritis Outbreak Summary.

"2003 Outbreak of Escherichia coli 0157 Infections Associated with Consumption of Alfalfa Sprouts produced in Minneapolis"  Kevin Elfering, Program Director, Dairy, Food and Meat Inspection Division, Minnesota Department of Agriculture.