Fresh Labels 11 Dec 2008

Naoki Hirota's Fresh Labels change colour to reflect the "freshness" of the products to which they are affixed. As you can see in the images above, they start off white, then gradually turn blue as the meat (or other perishable product) heads towards its "sell by" date. What we particularly like about them is that, upon turning completely blue, they obscure their barcode, making them unscannable at the tills (and thereby ensuring that no consumer accidentally buys an out-of-date item).

How do they work? Well, they use special ink that's reactive to ammonia and made of a non-toxic - safe - pigment extracted from purple cabbages.