Member services can fax you the order form (I don't think it's online, but I could be wrong). But ordering groceries to be delivered is about as expensive as purchasing them at the resort store - which is to say, very expensive. The list that MS has is basically what they carry in the Resort store as well.
if you are renting a car, there are a number of less expensive store options nearby; if you aren't renting a car, many of the town car services that run between the airport and WDW will offer a free 1/2 hour grocery stop (let them know when you make the reservastion for the towncar that you want this).