Andria treat is a 68-year-old woman in reasonably good health, although overweight. she takes a daily multivitamin supplement and almost daily over-the-counter antacids for heartburn. she says she eats mainly lean meat, chicken, fish, and seasonal fruit and fresh vegetables from her garden. she now reports having severe heartburn. also, over the past two days, she has had painful stomach cramps and diarrhea. she reports that she attended a family reunion picnic two days earlier.
based on her history, what is a likely explanation for mrs. treat's sudden onset diarrhea?