Where to report improper food handling of restaurant?

You could start by talking to the manager/owner. I doubt that they waht to be selling food with gl in it. This might also indicate a disgruntled employee at the restaurant that management should learn about. If you want to go to official channels, contact your local government (the main number will do). Tell them what you want to report and they'll connect you to the right department. If your child ate any gl, you'd probably know right away, but watch her for the next day. If she's showing any distress, I'd recommend taking her to an emergency room.