black lab aggressive with food

Question
My black lab mix pup is about 10 months old and she is usually very loving and affectionate. Recently she has become very aggressive with her food and her rawhides and if she even thinks you are going to touch them she will barkl, growl and snap. Now, I have been told by some that this is normal behavior and not to correct it because she is technically not doing anything wrong.  And other people have told me that I am to be the "alpha dog" and as such she should not be allowed to show aggression towards me. Who is right? Is this behavior that should be corrected? If so, how do I do it without getting bit??

Answer
At one time I would have said get tough.  The dog guide school is teaching me more positive methods.  

Only put part of her food in her dish.  When she finishes it, put more in her dish.  That will very quickly change her attitude towards having your hand near her dish.  

The pet stores are full of toys that many dogs will quickly chew up into pieces they could choke on or cause intestinal blockages. If you are not there to watch, stick to sturdy stuff such as Nylabones and Kongs. Keep a close eye on chew toys and quickly discard anything that is coming apart in pieces. Rawhide is especially bad because it swells after being swallowed. I don't trust any of the consumable chews. The dogs just gnaw them down to a dangerous size too quickly. These problems are the worst with, but not limited to, large, aggressive chewers such as Labs.

Ropes from the pets' store quickly turn to hazardous shreds. Ones I made lasted much better. Go to a hardware or home center that sells rope by the foot. Buy 2' of 3/4" poly rope. Melt the ends, and tie knots in it. Get them as tight as possible, put it in a vise and pound it with a hammer. Watch carefully, and be ready to discard when it comes apart.