If you don't mind asking... You've known for 9 or so years that the dog was food aggressive... Why was nothing ever done to curb that?
Train your dog by taking his food from him, while eating, regularly. This will get him used to it and will start making him non-aggressive with his food. Have set eating times (dont leave food out all day) and do not let the dog remove the food from the dish to go elsewhere. Getting them to not remove their food is very easy, i had to do it to my puggle, it just takes some time and you just have to correct her everytime she trys to remove the food.
1st, I'm glad your child is okay but Mooks question is the first thing that popped into my head as well....
I myself was bit in the face as a child by the family dog when he got up on the table and got a donut off the table. Didn't want him to eat chocolate, tried to take it away, got bit in the face.
You need to decide if you want to put in the time and effort to get this resolved (and it'll be a lot of it, so be honest about this answer) first and foremost. After being bit by my own dog because of food aggression I vowed to make sure this doesn't happen with my current dog. Just like tinfoilhat mentions you have to have your child involved with the whole process. Keeping them apart is not the answer in my opinion.
I'm not saying have your child put their hand in the food dish, but I would have him be the one to put the dogs food on the ground. Make sure the dog sits and waits patiently while your son holds the bowl, then puts it down after the dog has waited awhile.... Then you have to be able to take the food away from the dog at any time you want.
Myself, I put my hand in the dogs dish.... use my hand like another dog and push her outta the way so only my hand is in there.... take the food away entirely.... take the food out of her mouth on occasion... etc. Every time I do this she now sits down and waits for me to finish whatever I'm doing before going back to eating.
The same goes for toys as well. When I see her getting way too excited with a toy, it gets taken away until she calms down some and then she gets it back. Tug of war games start when I say go and end when I say stop.
In the end, they're still dogs though and dogs use their mouths to communicate especially with other dogs. The biggest thing you can do is teach your dog to always use a soft mouth. Mine is still a puppy but we've been working on soft mouth stuff for awhile now and it's made huge strides. She use to draw blood often with those damn little puppy razor blade teeth, but has slowly used less and less pressure. She's still teething so chewing on stuff like crazy but I no longer need band-aids after a long play session. Retreivers are naturally great at soft mouths (they're bred to bring back water fowl without puncturing it), and terriers are harder because they weren't bred to have soft mouths... In the end though, any dog can be trained to have a soft mouth.
All in all, just ask yourself if you think it's worth all the work, and be honest with yourself about it. If it is worth it, go for it and keep everyone involved.
