David Acheson, U.S. Food and Drug Administration's associate commissioner for foods, called the discovery "a very important break" in leading investigators to believe jalapeno peppers are the source for the continuing salmonella outbreak, Healthday reported.
The FDA on Thursday gave the all-clear signal for fresh tomatoes, originally believed to be the outbreak's source.
Acheson said while the contaminated pepper was grown on a Mexican farm, "that does not mean that the pepper was contaminated in Mexico."
The FDA shared the information with the firm and a recall is under way, Acheson said.
"While this one sample doesn't give us the whole story, this genetic match is a very important break in the case," Acheson said. "This will ultimately, hopefully, allow us to pinpoint the source of the contamination, which has caused the outbreak."
A warning issued last week against eating either jalapeno or serrano peppers for people at risk of infection, including infants and the elderly, remains in effect.
Since April, 1,220 persons were reported infected with Salmonella saintpaul in 42 states, the District of Columbia, and Canada, the FDA said.