The salmonella outbreak seems to be finally winding down, but the FDA still can not yet say how the few tainted Mexican peppers they have found could explain such widespread illness.

The outbreak is not considered over yet, Food and Drug Administration food safety chief Dr. David Acheson cautioned on Friday.  The outbreak strain has been confirmed in 1,423 patients, with the latest known illness beginning July 24 according to the CDC.

The FDA is focusing its probe on farms in Mexico where a handful of jalapeno and serrano peppers, and some irrigation water, tainted with the outbreak strain of salmonella were traced.  At least one of the farms also grew tomatoes — the initial suspect — as well as peppers.  And two of them sent produce to a common packing facility.