Of all the things in a supermarket
, things in tin
s are the last to rot.
The adjective ambient creeps in there because Ambient Canned Goods do not need to be kept chilled; an ambient (or room) temperature is OK. I think I picked this term up when a manager of a big store used it on the radio.
Apparently, when panic buying begins in a crisis situation, the fresh good (bread and milk etc) are first to go. People start buying Ambient Canned Goods in huge quantities when the Widespread Panic really kicks in. Their attraction is that they have a shelf life of years rather than months. This makes them A Good Thing to stock up on if food looks scarce.