Hi John
I would like to start out by saying good for you on rescueing her - she is the kind of dog I rescue to rehab so I know exactly what you are going through. I have experience with aggressive and dominant rescues and clients dogs.
First, The ecollar training is a huge waste of money. I am sorry btu 800 for 4 lessons? That is absolutely ridiculous. I personally do not use ecollars for most aggression problems, at least not at first. If I use an ecollar it is for fence charging/fence fighting/at a distance work.
Forfood aggression while I will agree with previous posters, the alpha does not take food it has already given. BUT you are currently not the alpha. Also, if you get a dog that is already food aggessive it must be worked with and the only way to do that is to "mess with its food" and the like, it is completely different from raising a dog and choosing not to bug it while it is eating.
This dog needs a strict routine. I recommend a DD collar (
http://www.leerburg.com/746.htm ) and a muzzle, for your safety. If you can find a trainer that is experienced with dominant aggressive dogs it will be in your best interest to find that person and bring them in on the work. I never recommend someone who has never done it before to attempt to work with a dog on food aggression/resource guarding/handler aggression. I still suggest the DD collar and the muzzle, to be used for Obedience and pack structure work for your safety. I also recommend the Dominant Aggressive Dogs DVD (
http://www.leerburg.com/301.htm )
To start, once you get a muzzle for her, work with her on sit and down first (have you obedience trained a dog before?) and her feeding time needs to be structured. She needs to work for her food and only be given her food if she is calm. A crate is generally a must and it is in this case also, if you don't already have one. Until you get a muzzle and work on the Obedience I would feed her in the crate so you don't have to come in contact with her. If she becomes aggressive about opening the crate because the bowl is in there, I like to drill a hole in a thick plastic bowl and attach a leash to it, I stand on the opposite side of the crate door from where it opens, reach across to open it and as soon as it is open I pull the bowl out with the leash. Don't touch the bowl with your hands, dangle or drag it to where you want it out of reach of the dog. I rarely do this but I have in the past.
Once again I will repeat, unless you can get a professional that is experienced with this exact type of behavior, don't work with her without a muzzle, for your own safety. If you are not sure how to put a muzzle on or would be nervosu to do it, put a dab of peanut butter on the inside bottom edge at the tip of the muzzle, let her sniff it through the open muzzle, let her lick it (don't put enough to be more than a lick or two, like a dime sized amount) and after doing that once or twice, put it on her while she is licking it out and it should be easier than just trying to force it on her and risking a fight.
What is her behavior aside from food aggression, jumping up on the counters, stealing food, not listening? Oh and also I would not be so sure she has never been trained. A dominant dog can and will completely ignore someone giving a command.