About 20 fourth-graders at New Brighton Area Elementary School in Beaver County were sent home Tuesday after eating undercooked chicken and complaining of feeling sick.

The district sent a letter home with the students explaining to parents what happened and providing information on the symptoms and treatment of salmonella enterocolitis, also known as salmonellosis.

One tray containing 30 servings of chicken was served to the fourth-graders during the 11:30 a.m. lunch period. The superintendent said it appears one of the cooks was putting several trays of uncooked chicken into the oven and pulling several trays of cooked chicken out of the oven when a mix-up occurred.

Richard McGarvey, a spokesman for the Pennsylvania Health Department, who explained that the health department is usually notified by physicians or hospitals after a contagious illness has been confirmed, said it was good the school warned parents so that the children can receive proper care.