huh, but dry ice is just carbon dioxide in its solid form
but im looking into it to see if theres anything to it, but i really dont think there is right now, only things i can think of would be that as it "melts" it displaces the oxygen and lowers the concentration making it less likely to react with your food, other things are that it could react with oxygen free radicals to make 2 carbon monoxide particles
but it would almost certainly put your container under pressure, which could run the risk of it not being airtight any longer
anyway im looking for some actual scientific evidence of it and why it works xD