A smartphone app could replace use-by-dates in an attempt to cut down on food waste, researchers at Imperial College London have said.

Bioengineers have created “paper-based” sensors that can be printed onto food packaging to detect spoilage gases like ammonia and trimethylamine in meat and fish products.

Consumers can then scan their smartphones over the sensors to see if their food is safe to eat.

Researchers hope that the technology will be available in the UK within the next three years to help reduce the £12.5 billion-worth of food thrown away in the UK every year that is safe to eat.

The biodegradable sensors, known as PEGS, were made by printing carbon electrodes onto readily available cellulose paper.