Expiring Date Info Colored Stickers for Grocery Shelved Items Would be Useful

 It might be useful for grocery store items like canned food to have chemically timed sell by date stickers that change color as they move toward expiration. Certain batteries do. The stickers could be installed by the manufacturer and might be available to grocers to buy and apply labels themselves that activate on exposure to air perhaps.

It isn't always easy for workers rotating stock to know when it expires... Customers to aren't always aware of the freshness of merchandise and it would save much time if a glance provided as much information as a check of small print on each product for shelf stockers to see if some stock needs to be rotated or taken down.

Alternatively there might just be a simple standard colored code different for each month of the year manufacturers could place in a small round sticker on each item sent to grocers so there is at least approximations of an expiration date.