I completely sympathizethat is every parent's worst nightmare! Organic spills like that contain strong acids that can permanently discolor the fabric and leave bacteria deep in the foam. I faced the exact same mess last year and called Chicago Couch Cleaning https://chicago-couchcleaning.com/ immediately. They used hot water extraction along with eco-friendly sanitizers that neutralized the acid and flushed the bacteria completely out of the padding. For thorough professional upholstery cleaning services in Chicago after a health disaster, they are the absolute best. The sour smell was gone instantly, and the cushion was completely disinfected and safe for the family again!