Your service dog should not be picking anything up unless instructed to do so. You will fail the Public Access test if your dog picks up a piece of food off the floor.
Leave it is important for several reasons. It could be live saving if your dog is going for something that is potentially poisonous. It also teaches restraint and self-control. It is a recall. Start training this as soon as you get your puppy. If you have an adult, start training it now.
Leave it is important to a service dog as it is one of the tests that your service dog should pass.
To teach Leave it, put a small piece of food in your hand. Let your puppy or dog sniff it and try and get the treat. As soon as they back off, tell them yes or good and give them the treat. Repeat until your dog consistently backs away and waits for you to give the treat. Now add the words “leave it” and repeat.
Try it now with your palm open and the treat visible. Say leave it and if he goes for the treat, close your fist so he can’t get it. Try again until he does not go for the treat and then reward.
Now try the treat on the floor and sit close to the treat so you can cover it if needed. If he doesn’t go for the treat, give him his reward from your hand. Put a leash on your dog, drop a treat and if he doesn’t go for it, treat from your hand…and of course, tell him what a good dog he is.