Think about it. What do you put into a seatback pocket? Likely things like old water bottles, used tissues (ew!), and food wrappers. Seatback pockets are also the go-to repository for airsickness bags. That’s why you should think twice about using the pocket to store food or beverages. Also, realize that the stuff that’s already in there when you get on the plane (the magazine and safety instructions) may be riddled with bacteria, too.