omaha steaks packs their items in dry ice and overnights them...but those are meant to be consumed...so you wouldn't have to take those kind of precautions with auction food items...i would think overnighting the item would be sufficient...dry ice evaporates within 24 hours...It would depend on what type of climates you think it would be traveling through...if it was going through mexico you'd want to use dry ice and overnight it...otherwise the item may be very rank by the time it reaches the winning bidder...if it is going through canada during the winter you wouldn't need dry ice....If the item does not require being frozen..like a piece of toast...you could just send it snail mail in a zip lock baggie
I used to work for Omaha Steaks, yes they use dry ice a lot.
In a food listing, I would just say shipping is up to the buyer. To be honest most people don't care about what they are bidding on, they just want the publicity as the winning bidder. If I won a cheeto or a dorito, I would just say put it in an envelope and send it LOL! I don't really care if I get it smashed or not. I would even say that in your listing.
"Shipping can be a 32 cent stamp and an envelope, or a more secure package. This is totally up to the winner."
Will make more people bid, because most people don't care about the item and would rather bid a penny knowing the shipping will be 32 cents, than a penny knowing the shipping is 10 dollars. The only time you have to worry about shipping padding and stuff is when the item sells for a lot. Then the people have more money anyway and most likely want the item for novelty-sake and for promotions.