5 month old cocker spaniel agression with food

Question
Does anyone knows how to stop my cocker from growling if anyone gets near him when he is eating.  He has bitten when I tried to take away paper soiled with food that he had taken from trash.  I have tried grabbing him from his back, spraying with water and shaking a can full of coins that normally helps stops other unwanted behavior.  Nothing stops the food aggression.  Any ideas.

Answer
Hi Marcia sorry im no expert with this, to be honest my advice from my own experience is make the dog wait and sit while you put the food then tell him to eat and walk away, if you need to pick up the dish or paper before the dog has finished its meal stand near the bowl and tell the dog to leave, this will obviously have to be repeated over and over again, but to be honest would you like your food taken off you if you were eating it and enjoying it, my advice is let your dog eat in peace when he has finished, make him sit and wait pick up his bowl and praise him for letting you pick it up and finishing his meal.
My other advice is if you join up to Cockersonline as a free member, you will get so much helpful information and they are all so friendly, i have learnt so much as a cocker owner its a great site.
Good Luck
Kathy