The outbreak strain is a specific type of the bacteria called Salmonella Javiana. Investigators confirmed the cases were connected using whole genome sequencing, a kind of genetic fingerprinting that showed the bacteria from sick people were closely related, pointing to one shared food source.
That detective work led to jalapeños in a fairly convincing way. Of the 191 people interviewed about what they ate in the week before falling ill, 177, or 93 percent, reported eating at a Mexican-style restaurant, according to the CDC's investigation update. Investigators then identified 27 separate illness clusters at Chipotle and QDOBA locations in seven states, where the commonly reported ingredients included jalapeño peppers, red onion, cilantro, and avocado.
From there, a traceback investigation narrowed the trail to its origin. The FDA determined that a common grower in Sinaloa, Mexico, supplying Coast Citrus Distributors, was the likely source. At the agency's recommendation, Coast Citrus agreed to recall the remaining product and has stopped importing from that grower.
The people who got sick spanned nearly every age, from under 1 year old to 85, with a median age of 30 — a reminder that healthy adults, not just the vulnerable, ended up ill.