The U.S. Centers for Disease Control reported that as of 11:00 AM EDT on May 26, 2010, a total of 28 individuals infected with a matching strain of Salmonella Newport have been reported from 10 states since March 1, 2010. The number of ill people identified in each state with this strain is as follows: AZ (2), CA (14), CO (1), ID (3), IL (1), MO (1), NM (1), NV (2), OR (1), and WI (2). Among those for whom information is available about when symptoms started, illnesses began between March 1, 2010 and May 7, 2010. Case-patients range in age from <1 to 75 years old, and the median age is 32 years. Sixty-four percent of patients are female. Among the 20 patients with available hospitalization information, 6 (30%) were hospitalized. No deaths have been reported.

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 are currently ongoing at the sprout processor.

On May 21, 2010, J.H. Caldwell and Sons Inc. of Maywood, CA, recalled several brands of alfalfa sprouts distributed to wholesale distributors, restaurants, delicatessens, and grocery stores.