Food in wizarding world

[Kim]

No: HPFGUIDX 76296

Hello,
This is an insignificant point, but one that has been nibbling away 
in my mind since my first reading of the first book.  I wonder about 
how wizards procure their food.  Do they have grocery stores or 
markets?  We don't hear about any markets in Diagon Alley (that I can 
remember), just the ice cream parlor.  We know that there are pubs 
and sweet shops and the like, both in Diagon Alley & in Hogsmeade.  
But where does a wizard or witch go when they need a can of tuna or 
some peanut butter?  Surely they don't go to the Muggle market.  Do 
they just summon their groceries?  Do they have a running tab at a 
wizard market somewhere (I can just picture tins and boxes zooming 
off the shelves as they are summoned)?

Another point along the same lines - I know finances are extremely 
tight for the Weasleys.  But they always seem to have plenty to eat 
for all those growing kids.  One teenaged boy can eat a family out of 
house and home, let alone having 5 teens or near-teens at home.  And  
Molly seems to pride herself on filling Harry up when he arrives, 
half-starved, from the Dursley's.  In fact, they seem to take guests 
in their stride - I don't get the sense that Molly is fretting about 
adding another potato to the soup.  I don't remember there being any 
livestock at the Burrow, from the canon descriptions.  How do they 
put such copious amounts of food on the table?  

Perhaps I've overlooked something, but this detail has been bugging 
me for long enough!  Help, anyone?  Thanks.
pax
Kim