Hello,
One of our B's had similar biting issues - she had been raised in a pack with a lot of competition, and she had never learned that a treat or a toy must be released on command. I applied Cesar Millan's approach and it worked beautifully, the first time and within 15 minutes!
1. Show the dog the treat, make her sit and stay, and make eye-contact.
2. As she calms, bring the treat closer and stay in eye contact - she must stay calm-submissive throughout.
3. Put the treat on the ground in front of her - use your posture, body language and voice to keep her calm-subm.
4. Then release her to get the treat.
5. After a minute or so, order her to release. If she doesn't, a little Cesar-prod to the side will help to snap her out of her state of mind.
6. Repeat the whole process, until she releases the treat at first command.
7. Repeat the next day.
Be patient and follow through all the way to the end - Binti got it really fast that we wouldn't let up and she changed accordingly.
I'm sure you can find videos on Cesar's site or National Geographic with similar episodes - it works!
All the best,
Kees-Jan Donkers, The Netherlands