CDC has been collaborating with public health officials in many states and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of Salmonella serotype Newport infections linked to the consumption of raw alfalfa sprouts. Investigators used DNA analysis of Salmonella bacteria obtained through diagnostic testing to identify cases of illness that may be part of this outbreak.
As of June 24, 2010, a total of 44 individuals infected with a matching strain of Salmonella Newport have been reported from 11 states since March 1, 2010. The number of ill people identified in each state with this strain is as follows: AZ (4), CA (19), CO (1), ID (6), IL (1), MO (2), NM (2), NV (4), OR (2), PA (1), and WI (2). Among those for whom information is available about when symptoms started, illnesses began between March 1, 2010 and June 1, 2010. Case-patients range in age from <1 to 85 years old, and the median age is 38 years. Sixty-eight percent of patients are female. Among the 34 patients with available hospitalization information, 7 (19%) were hospitalized. No deaths have been reported.
The outbreak can be visually described with a chart showing the number of people who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after June 11, 2010, might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks. For more details, please see the Salmonella Outbreak Investigations: Timeline for Reporting Cases.
Investigation of the Outbreak
Collaborative investigative efforts of many local, state, and federal public health, agriculture, and regulatory agencies have linked this outbreak to eating raw alfalfa sprouts. Interviews of case-patients found that most reported eating raw alfalfa sprouts before becoming ill. Some case-patients reported eating sprouts at restaurants; others purchased sprouts at grocery stores. The initial investigation traced the implicated raw alfalfa sprouts to a single sprout processor in California. Investigations were conducted at the sprout processor.
On May 21, 2010, J.H. Caldwell and Sons Inc. of Maywood, CA, voluntarily recalled several brands of alfalfa sprouts distributed to wholesale distributors, restaurants, delicatessens, and grocery stores.