Ah, more information...this is good.
Oh I am not putting your breeder down but if they do use/work with the Volhard Puppy Aptitude program then your little one will be frightened if you flip it on its back and that is not good.
Since she is being good with the kids (don't let her get use to this or you will be hand feeding her the rest of her life..
) and with the other dog then she is not food aggressive but you gave her a treat that made her crazy. Do you think it was the first time she has ever had this treat? Even mine who lets me do just about anything (except grooming with one) won't let me have their treats and I leave them along. Maybe once she realizes these treats are not that special she will relax but when you go to take a treat away you must be ready to replace it with something else to divert her attention.
I don't think it hurts to take food away and then put it back down so she gets use to your hand being around her food bowl.