A strain of the salmonella bacteria that sickened more than 1,300 people has been found in a serrano pepper and a sample of irrigation water at a farm in Mexico, U.S. health officials said Wednesday.
They called the discovery a "breakthrough" but cautioned that tomatoes may still be a culprit in the nearly four-month outbreak that has alarmed consumers and cost the domestic produce industry hundreds of millions of dollars.
"We have a smoking gun, it appears," said Dr. Lonnie J. King, director of the center for food-borne illnesses at the Centers for Disease Control and Prevention, in testimony at a congressional hearing.
The rare Salmonella Saintpaul strain was found at a farm in Nuevo Leon state in northeastern Mexico, said David Acheson, food safety chief for the Food and Drug Administration. The farm grows serrano and jalapeno peppers but not tomatoes, he said.
Contaminated water is a common launchpad for salmonella, experts said. Fecal matter can seep or be washed into wells, canals and other untreated water sources used to irrigate crops, said Douglas Powell, scientific director of the International Food Safety Network at Kansas State University.
Health inspectors found salmonella in a jalapeno last week at the Agricola Zarigosa produce distribution center in McAllen, Texas. However, Acheson said studies of victims showed that the Texas distribution center was not the source of the outbreak, and that the tainted pepper originated at a farm in Mexico's Tamaulipas state, east of Nuevo Leon.
And on Monday, the Colorado Department of Public Health and Environment said that a jalapeno purchased at a Wal-Mart in late June by a person who later fell ill tested positive for the Saintpaul strain.
No tomatoes have tested positive for the strain.
On Wednesday, lawmakers pressed King and Acheson about the slow pace of the investigation, traceability standards and conflicting messages about what was safe to eat.
In early June, the FDA issued a warning against three types of tomatoes, leading some retailers to pull all tomatoes from their produce bins. The advisory was lifted in mid-July -- not because tomatoes were in the clear but because any affected fruit would have spoiled by then.
A week later, the agency said that only jalapeno peppers from Mexico were linked to the outbreak. The FDA is now telling consumers that domestic tomatoes and peppers are in the clear, while fresh jalapeno and serrano peppers from Mexico should be avoided.
