re: Can you train aggressiveness out of dogs?

For food aggression:
As a previous poster said leave it is good for this. Practice leave it with the food yourself then with another person. Once you have that down, do leave it then give a bit of food to the other animal. Keep a leash on your aggressive dog just in case. It should teach restraint with others present. If doing this with normal food doesn’t work, try special treats like dry freeze food.
With the info provided, that would be my suggestion.
Also, we don’t give my dog food until we instruct her to eat. She must be called, sit, then told ok. If you don’t do this, try this as well. You can try leave it with the food bowl after the dog gets used to being commanded when to eat.
In general, I suggest keeping a leash on your dog even in the house if it is aggressive. Consistency is key. Work on this every time you feed your dog. Maybe 30 minutes before breakfast and then 30 minutes before dinner.