JACKSON, Mich. (AP) — Maggots were discovered in food at a Michigan prison during three incidents last summer.

The Detroit Free Press says they’re the first discoveries since Trinity Services Group was hired to supply food in 2015. The newspaper cited documents obtained by a Corrections Department employee.

Prisons spokesman Chris Gautz says any food problems typically are related to a lack of experienced staff. Trinity Services didn’t respond to a request for comment.

A corrections officer, Sgt. Michael Demps, says he saw four or five “worm-like bugs” still moving on a prisoner’s tray at the Cotton prison, near Jackson, on July 26. Records show “crunchy dirt” was found in a potato dish.

Trinity replaced another contractor that had problems. Gautz says it’s not known if Trinity’s contract will be extended next year.