[laininthewired]

Would you say this method works with all food items? I know that they cant ask for proof of food item making you sick but im wondering if how consistent will it be

It has a very high success rate, for the reason that the food Industry takes health & safety very seriously.

Im guessing that you can only do this for 1 item. IF you bought multiple you cant say everything made you sick

Honestly you could get away with saying that. You may have to fabricate a story that involves the entire contents of the box spoiling.