The infections were linked to raw clover sprouts in the six states.
Epidemiology and traceback investigations indicated that contaminated raw clover sprouts produced by Evergreen Fresh Sprouts, LLC of Idaho was the likely source.
Evergreen Fresh Sprouts is no longer using the seed lot linked to illnesses in this outbreak.
Sprouts produced by this firm from this seed lot are likely no longer available for consumption given the approximately 14-day shelf life of raw clover sprouts.
FDA investigation
In an US Food and Drug Administration (FDA) investigation, tennis rackets were found being used to scoop mung bean sprouts onto the conveyor belt during inspections at the facility.
The same rackets were used the following day in the bubbler during alfalfa sprout harvesting.
The agency also observed condensate and irrigation water dripping from rusty valves; a rusty and corroded watering system in the mung bean room; and a squeegee (used to agitate mung bean sprouts inside a soak vat) that had visible corroded metal and non-treated wood.
It conducted three inspections of Evergreen Fresh Sprouts on May 22-23, May 27-30, and June 6.
FDA and CDC held a meeting with the owner of Evergreen Fresh Sprouts in June.
The owner informed the FDA that the firm planned to discontinue using the sprout seed lot that was used to grow the sprouts linked to the outbreak.
CDC case details
The number of ill people identified in California was 1, Idaho (3), Michigan (1), Montana (2), Utah (1), and Washington (11).
44% of ill persons were hospitalized. No ill persons developed hemolytic uremic syndrome (HUS), and no deaths were reported.
Among persons for whom information was available, dates that illnesses began ranged from May 1 to May 20, 2014.
Ill persons ranged in age from 11 years to 52 years, with a median age of 27 years and 68% were female.
In interviews, 13 (81%) of 16 ill people reported eating raw clover sprouts in the week before becoming ill.