There've been a few scandals in Japan involving food providers tampering with expiration dates, but if every perishable product had these Fresh Labels, tampering wouldn't be an issue: These stickers can never lie.
The Fresh Label design works by detecting ammonia emanating from the product within and fading out accordingly. Once the ammonia level reaches a level deemed unsafe, the label will no longer be readable. It's a clever system that can't easily be manipulated, and provided it's reasonably cost-efficient, we could see it being adopted in large scale. Until then, follow the same rule as when choosing a possibly-dirty shirt from the laundry pile: If it smells funky, put it back. [Swiss Miss via Serious Eats