Switching on to food gone off

Better out than in: a new ink might help to betray the presence of oxygen in pre-packed food.

Without oxygen, life as we know it would not exist. However, this crucial gas is also a key player in chemical reactions that accelerate food decay, so manufacturers are keen to exclude it from their packaging, to keep our groceries as fresh as possible.

Proving that a sealed inert environment has not been violated by oxygen has until now been a technological challenge. However, Andrew Mills and colleagues at the University of Strathclyde in the UK have developed a promising cheap ink formulation that, once activated by UV-A light, transforms into an irreversible indicator that can be printed onto many suitable surfaces, betraying the presence of oxygen at a glance.

Using this simple ink in food packaging would provide reassurance to the consumer and manufacturer alike. The researchers point out that its benefits could be extended to any packaged material requiring a protective atmosphere, such as pharmaceuticals and delicate museum pieces.

Sula Armstrong