Undercooked chicken served at the Suffolk jail in Riverhead led to a salmonella outbreak that sickened at least 21 inmates in May, health officials said.

One inmate who was hospitalized has filed a notice of claim with the county, a prelude to a lawsuit.

“Suffolk County comes with an affirmative obligation to supply its criminals in prison all food that’s free of any unhealthy or dangerous substance,” stated Andrew Siben a Bay Shore attorney representing the inmate, Shawn Carpenter.