This happened yesterday.   I am at the Giant supermarket in Bethesda,  and they have 2 pints of blueberries for the price of one $4.99,  and they are very good this time of year from Michigan, but I still try one or two to make sure,  and then look at the bottom of the clear containers to make sure there aren't a bunch of crushed ones.  So I pick my two out and some guy comes over and stands right next to me and asks me how did I know those were good and to pick those two out.   I demonstrated you open the lid and take one out and taste it,  he looked at me with incredulity (definitely a pajama boy) and he said "but you aren't supposed to do that!"   And I said "theoretically you are exhaling too much carbon dioxide so what do you???  Taste the blueberry or turn yourself in to the EPA??"