This is brilliant and worthy of an award of some sort, like a good design award. To-genkyo have come up with a label that figures out when the meat inside has gone bad. No more relying on iffy smells or dodgy colors, the label actually spells it out for you. It's really quite simple, the ink is ammonia-detecting ink and it will darken depending on the level of ammonia present in the enclosed meat. Without the label trust the old saying; red meat isn't bad for you, fuzzy blue-green meat is bad for you.