Tesco is recycling, Asda is using trains and Sainsbury’s is composting: what next in the supermarket green wars? It could be edible packaging. This green consumerism doesn’t require even a trip to the compost bin — just a chew and a swallow, like a spy destroying his brief.

Javier Osés Fernández, a chemist at the Public University of Navarre in Spain, has been playing around with edible coatings and has found a compound of milk serum protein, glycerol and mesquite gum to be the most resistant to changes in temperature, humidity and leakage from food. The film was especially good at protecting fatty foods such as nuts and meat that are at risk of oxidisation.

Meanwhile Biopac, a British company, is researching an odourless, tasteless edible coating for extending the shelf life of fruit and vegetables. Derived from milk whey, it contains anti-bacterial compounds.

A quarter of all household rubbish — 4.5 million tonnes — is retail packaging, much of it from food. So anything to reduce our hideous contribution to landfill is welcome. But we may not be chowing down on the cheese wrapper any time soon: like most infant technologies, edible packaging is expensive to develop.