COLUMBUS, Ohio (AP) — Officials say they are closer to finding the source of botulism that killed one person and sickened many more after a church picnic in central Ohio last weekend.

Ohio Department of Health spokeswoman Michelle Loparo said Friday that six food samples retrieved from a garbage bag at the church have tested positive for botulism.

Four of the samples were potato salad, along with a sample of macaroni and cheese and a spaghetti pasta salad. Since they were all in the garbage together, more testing is required to determine which of the foods was initially contaminated.

A 55-year-old woman died from botulism after the Sunday potluck at Cross Pointe Free Will Baptist Church in Lancaster. Nineteen other botulism cases have been confirmed, in addition to nine suspected cases.