Try this. Do not start fixing her food when she starts screaming. Ignore her screaming. When it is time to fix her food, go ahead and do so. Hold the dish in your hand and stand quietly looking at her, until she stops screaming.
If, as you start to set the dish down, she starts screaming, pick it right back up and hold it, standing quietly and looking at her. When she stops screaming, start to set the dish down. If she starts screaming again, don't set the dish down, lift it back up and go back to quietly looking at her.
It may take a few to several times of doing this, and it is repetition that helps the dog figure it out.
Never again give her a dish as reward for screaming. The screaming for food will end when it no longer works for her, and she realizes it no longer works.
Don't yell, punish, etc. Just wait her out.
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Kathy Diamond Davis, author, "Therapy Dogs: Training Your Dog to Reach Others," 2nd edition, and the free Canine Behavior Series articles at http://www.veterinarypartner.com/Content.plx?P=SRC&S=1&SourceID=47