<human>: Alright, so today we picked up on of those rolling treat dispensers that has to be pushed around for the food to fall out. Our puppy, a 5 month old Pit Bull, was given his lunch in it and then his dinner. It was pretty much empty, and there was some food he missed on the floor. Our other dog, a 7 yr old Lab was in the room too, and had eaten some of the food on the floor. Well, the puppy saw her, and he kind of paused to stare at her and then went after her. Thankfully I was right next to them and pulled him away and the Lab went into her crate. I thought there was no more food left on the ground so I called her back, while holding onto the puppy's collar, to make sure she was ok, and she found one piece of food and ate it and the puppy went back after her. I was still holding him so he didn't really get to her, but it was pretty scary. I have never seen him do something like this. The dogs are separated when they eat, but that is mainly because the puppy will try to eat the other dogs food, and I hadn't really thought about him being protective of his food. From day one i've made sure he had some boundaries when eating, making him sit and wait, petting and touching him while he eats, and putting my hand in the food and just move it around. 

I know this means the other dogs probably cant be in the room until he is finished eating, but i'm worried he's going to start guarding his food around humans. What can I do about this? It really scared me to see him do this, and i'm afraid he's gonna get worse as he gets bigger. Please give me some advice, thanks.

Can you succinctly summarize the text in 1-3 sentences?
<bot>: My 5 month old Pit Bull pup went after my 7 yr old Lab when she ate some of his food off the floor, i'm worried about him starting to guard his food and would appreciate some advice.