The state Department of Health has identified a third strain of salmonella bacteria that may be linked to Roma tomatoes served at Sheets convenience stores that are believed to have sickened more than 400 people.

"This really doesn’t change anything for the general public," said health department spokesman Richard McGarvey. "We feel the contaminated source — tomatoes from Sheetz — was eliminated very promptly."

No new cases of salmonella have been reported for nearly a month.

Nearly all of the 330 cases identified in Pennsylvania — and more than 80 cases in other states — were linked to the Salmonella javiana strain. Four cases were linked to the rare Salmonella anatum, the same strain as found on Roma tomatoes from one Sheetz store.

While interviews are continuing, McGarvey said "all of the indications" show that the dozen cases tied to the third strain are linked to tomatoes at Sheetz.

Sheetz bought all of its sliced Romas from Coronet Foods, a Wheeling, W.Va., distributor that slices and dices produce. Ninety-nine percent of Coronet’s sliced Romas went to Sheetz stores.