Ahhh, yes, food aggression...my Danni can be like this...he challenges anyone new who comes near him. He doesn't challenge me anymore, but I have made him understand that I control the food and when it gets dispersed to him, and can take it away if necessary, to ensure other's safety.
I always make him back up and stand away from me when I am bringing him his grain after a workout; I reinforce the back up with a dressage whip to the center of this chest if necessary. I do not allow him to come forward to the grain bucket, until I ask. Then when I do, I do not allow him to rush the bucket, or pin his ears to challenge me, or tell me to 'move it'. If he does, I again, ask him to back it up, and wait.
I am teaching others to do the same; he challenged my hubby twice last night, and the second time I made him have Danni back off...Danni was like "what the???" He left DH alone after that...
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."