The Food and Drug Administration has identified another U.S.-based supplier of imported onions that have been linked to a major Salmonella outbreak, as the organization advises that onions should be thrown away if the source is unknown.

Announcing the outbreak on Wednesday, the FDA had listed Idaho-based ProSource Produce as the only know supplier of the onions from the State of Chihuahua in Mexico.

On Thursday evening, it said it had also identified Keeler Family Farms of New Mexico, as another supplier of the onions in question.

To date, this outbreak has been associated with 652 illnesses across 37 states, including 129 hospitalizations. No deaths have been reported.

ProSource Produce LLC has issued a voluntary recall of red, yellow, and white whole, fresh onions imported from the State of Chihuahua, Mexico, with import dates from July 1, 2021, through August 31, 2021. A full list of recalled product information is available in ProSource Produce LLC’s recall announcement.

FDA’s traceback investigation identified Keeler Family Farms as an additional common supplier of onions from the State of Chihuahua, Mexico for many of the restaurants where sick people reported eating. When FDA met with the firm, the firm agreed to voluntarily recall all red, yellow, and white onions imported from the State of Chihuahua, Mexico, from July 1, 2021, through August 31, 2021. More information regarding their recall will be provided once it is available.

Descriptors of impacted onion types from ProSource Produce LLC and Keeler Family Farms may include, but are not limited to, jumbo, colossal, medium, summer, and sweet onions.

These onions supplied by Prosource were sold to restaurants, food service locations, and retail or grocery stores throughout the United States. The investigation is ongoing to determine the source of contamination and if additional products or firms are linked to illness.

"Consumers should ask if the onions being served or sold were recalled by ProSource Produce LLC or supplied by Keeler Family Farms and imported from the State of Chihuahua, Mexico," the FDA said.

"If you still cannot determine if your onions were recalled by ProSource Produce LLC or supplied by Keeler Family Farms and imported from the State of Chihuahua, Mexico, do not sell, serve, or eat them, and throw them out."