How are retailers supposed to charge sales tax from state to state?What about on food items and non-food items?

I am about to launch an online gift basket site. It will have bagged food items and non-food items. Am I supposed to charge sales tax on the whole basket or just the non-food items within the basket? I think I may need a tax attorney. But i'd like to hear what you have to say...
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Congress says that online merchants need only charge sales taxes in those states where they have a physical presence -- ie: where you are. no sales tax need be collected on shipments to other states.
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