The first fruit or vegetable that begins to go off in an esky, most commonly a piece of broccoli. With a piece of broccoli, this becomes apparent as it begins to go yellow and limp. It signifies the short-lived future and imminent demise of the other perishable items within the esky, much as the death of a canary in the mines warns the miners that immediate action must be taken if they wish to live.
by ~Çŭnning-Liñgüist~ February 15, 2011