The state Department of Children and Families took custody of a 5-month-old girl left unattended Sunday afternoon in a hot car at the Mall at Whitney Field. The baby’s aunt, who was caring for the child at the time, pleaded not guilty during her arraignment in Leominster District Court Monday morning morning. Ruth Allende, 31, of Fitchburg, was charged with reckless endangerment and disorderly conduct. Allende was ordered held on $500 bail. Allende’s sister, Yajaira Muriel, 20, is the baby’s mother, according to police. A shopper noticed the infant in the locked vehicle about 5:45 p.m. Sunday. The windows were shut. It was 81 degrees at the time. Police were notified. Mall security officers used a tool to open the locked doors.