When you buy those empty food containers at your local miniature store, someone has already eaten all the mini food inside.  What a rip off, buying empty food containers, lol.  Well thank goodness for modeling compound otherwise our mini people won't get their fill of junk food.   So stock up your dollhouse, here's how I did mine:

After cooking the twinkies in the oven I put a dab of white paint on each end and three dabs on the bottom for the realistic Twinkie look.  Cut out a tiny piece of cardboard to set them on and wrap it up with Saran Wrap and there you have it, a full box of Twinkies at your service. 

The chocolate chip cookies are done with modeling compound too, although I have seen other ones that look a lot better than mine do here. 

Here are a few printables I got off of the web somewhere, I don't remember where so I can't give anyone credit for these.  If these printables are yours please email me and I will be sure to give you the credit for them on this page and a link to your website.

I took a small bag of Doritos from a vending machine and carefully tore it apart at the seams.  Then I scanned it and shrunk it down to 1" scale and printed it on photo paper.  You should also coat the print with a spray top coat since the inks from our ink jet printers aren't made to last forever on prints.

Glue the print at the back and bottom seams and fill the bag with tiny pebbles or whatever you can find to puff out the bag a little.  Then glue the top and squeeze the top and bottom seam with needle nose pliers (this will give you ridges on the ends from the ridges on the needle nose pliers, so it looks more realistic).  Now you have your very own handmade mini Doritos.  You can do this with any of the items you usually buy at the grocery store to personalize your food stock in your dollhouse to fit your taste and your budget.
I'm not sure if the Dorito bag is in scale so you will have to double check before you print it out.
MINI TIP:  I have seen people use crushed poppy seeds for the chocolate chips and they look much more realistic than my cookies do here.  I just haven't gotten around to redoing mine yet.