Diarrhea-Gate: One Sinaloa Farm, 345 Sick, And Two Restaurant Chains Down Double Digits

The FDA has finished tracing a multistate outbreak of Salmonella Javiana back to its source - a single grower in Sinaloa, Mexico, which entered the U.S. through Coast Citrus Distributors, a California importer that supplies restaurant customers.

The agency asked Coast Citrus to recall the product. The company says has done so, and is no longer buying from the grower.

The CDC has counted 345 confirmed infections in 27 states, including 36 hospitalizations and no deaths. Illnesses began between June 19 and July 20. The real number is likely higher: most people who get salmonella recover at home and are never tested.

The epidemiology was unusually clear. Whole-genome sequencing suggested the cases were coming from the same source, and restaurant histories pointed investigators in the same direction. Of 191 people interviewed, 177 - 93 percent - said they had eaten at a Mexican-style restaurant in the month ending July 14.

The restaurant chains, for their part, moved before the investigation became a national story. Chipotle changed jalapeño suppliers at affected restaurants on July 20. The company says its traceability system allowed it to identify the grower and lot involved, remove the peppers and replace them with product from other farms.

Qdoba took a broader approach and stopped serving jalapeños across the chain on July 28. Regulators now say neither chain represents a current ongoing risk.

Investors were less patient. Chipotle shares fell nearly 10% Tuesday and have kept sliding, closing Friday down almost 12% on the week. Sweetgreen, which uses jalapeños in only two of its fifteen dressings and removed them Thursday, fell 8% Friday and is down more than 16% on the week.

Of note, Sweetgreen had already seen July sales weaken amid concern over an unrelated cyclospora outbreak tied to iceberg lettuce - an ingredient the chain does not even serve. Once customers start worrying about contaminated produce, distinctions between one ingredient, one supplier and one restaurant brand tend to disappear quickly.

Mexican health authorities have opened a separate inquiry, meanwhile. Officials visited a packing facility this week in Nuevo Leon, which is in a different state from the grower identified by U.S. investigators.