The investigation continues into a nationwide outbreak of salmonella. Many grocerty chains are pulling some products with peanut butter in them from shelves, including outlets in Kentucky.But only three recent cases of salmonella in Kentucky have been linked to peanut butter, and those were reported last fall.Beth Fisher with the Cabinet for Health and Family Services says sometimes it can take several months to determine the source and range of these outbreaks."Especially with these outbreaks that affect so many states and there are so many people involved," says Fisher, "as you can imagine, that takes so much groundwork and so much investigative work, to trace what kinds of foods all those people ate, where those foods came from, it can really take a long time."Fisher says they’ve found no evidence of contaminated peanut butter products in Kentucky.The outbreak has so far been traced back to a Georgia-based manufacturer called Peanut Corporation of America.