Japanese design agency To-Genkyo proposes a dynamic freshness label for meat products. The hourglass-shaped label contains special ink that changes color based on the amount of ammonia emitted by the meat (the older the meat, the more ammonia it releases).
Hence you can easily read from the handy label if the meat is still fresh!! But wait.. could you not simple derive from the meat ITSELF if it is fresh? Well, some can perhaps, but nowadays most people can not 'read meat', so we need an authoritative label to tell us what we can and can't consume.
Elegant detail: When the meat is no longer suitable for sale, the ink blocks the barcode at the bottom so that it cannot be scanned at the cash register.