The basil was imported from a farm in Mexico's southern Baja California region on Dec. 5 and sold to food distributors in Southern California, Texas and Illinois the following day, said Alberto Martinez, a spokesman for Los Angeles-based importer Top Line Specialty Produce.
The Southern California distributor sold the basil to restaurants and other food service customers, but it was unknown whether the other distributors sold to food service customers or retailers, he said.
U.S. Food and Drug Administration inspectors detected the possible contamination during a random check of the basil as it passed over the Otay Mesa border crossing in San Diego County, Martinez said.
Top Line continued to import basil and other herbs from Green Paradise farm in the Los Cabos area, where the potentially contaminated product was grown, processed and bagged, until the FDA alerted the company about its inspection results on Tuesday, he said.
The company immediately stopped imports from that farm and issued its recall on Wednesday, Martinez said.
FDA spokeswoman Cathy McDermott did not immediately respond to a message left seeking details about the agency's test results and its involvement with the recall.
The "Green Paradise"-brand basil affected by the recall was shipped in sets of 12 one-pound boxes marked with lot No. 1219.
Salmonella can cause diarrhea, fever and abdominal cramps within 72 hours of consumption. It is usually found in food contaminated with animal feces, according to the U.S. Centers for Disease Control and Prevention.