shelf life is different from "expiration date". shelf life is linked to food quality, expiration date to food safety. a product that has passed its shelf life might still be safe, but quality is no longer guaranteed. in most food stores, shelf life is controlled by using stock rotation. this means moving products with the earliest sell by date to the front of the shelf, so that most shoppers will pick them up first and take them out of the store. this is important, as stores can be fined for selling out of date products. most shops, if not all, will have to mark such products down as wasted, leading to a loss of profit.