Pennsylvania, where Trump staffed the fry station at a McDonald's in suburban Philadelphia, has not been affected so far. But public health officials are continuing their investig

McDonald’s said it was taking “swift and decisive action” to control the outbreak that has sickened dozens of people, mainly in Colorado and Nebraska.

Nearly 50 people have become ill and one person has died, amid infections that may have been caused by slivered onions, the C.D.C. reported.