The onions imported from the state of Chihuahua, Mexico are now being recalled.
The FDA says there have been 652 reports of illness and 129 hospitalizations, but no deaths in the 37 states.
The U.S. Food and Drug Administration has identified onions imported by Idaho-based ProSource Inc. as the source of the outbreak.
The onions were imported from Mexico and sold to restaurants and grocery stores across the country.
ProSource Inc. has agreed to recall red, yellow and white onions with import dates from July 1 to Aug. 27.
Anyone experiencing symptoms of a salmonella infection, including cramps, fever and aches, should contact their healthcare provider immediately.