Supermarkets have defended themselves from claims some of the fresh produce on their shelves is up to a year old.

A report in the Daily Mail as highlighted the fact that potatoes can be preserved for up to nine months by being treated with ethylene gas. It adds that Kiwi fruit can be kept for eight months through refrigeration and apples are treated with SmartFresh gas to preserve them for up to a year.

Organisations such as Friends of the Earth said fresh produce should not be swamped with chemicals to preserve it.

But the major supermarkets have stressed they have a policy of sourcing local fresh produce wherever possible.