The flesh inside is orange, ripe and edible, but as a result of recent warm weather in Spain the skins have failed to turn the normal colour.

By selling the so-called easy-peelers with green skins that resemble limes, the supermarket says it will slash food waste by giving them up to two days’ extra shelf life.

Green satsumas are already in the shops and clementines – a Christmas favourite – will follow shortly. Tesco claims to be the first supermarket to relax the rules on this type of fruit.

“At the moment green easy-peelers fall outside of the general quality specifications set by UK supermarkets but Tesco has made the leading move in order to cut down on food waste,” said Tesco’s citrus buyer, Debbie Lombaard.

“As a result of this move to take out a handling stage in the journey from farm to fork shoppers will gain extra freshness for their satsumas and clementines.”

To accelerate the colouring process, Spanish growers in the Valencia region have been putting the easy-peelers into a ripening room, but this extra handling has led to a small amount of fruit being damaged and going to waste.

Satsumas and other easy-peelers, as well as oranges, initially grow as a green fruit but turn orange as nights cool.

Over the past few years warmer Spanish temperatures in the early growing season for satsumas in September and October have remained higher into the autumn, delaying the natural process by which the fruit turns orange.

Tesco’s “perfectly ripe early season satsumas” come in a 600g net bag and cost the same (£1) as conventional orange-coloured ones. Tesco, the UK’s largest retailer, sells nearly 15m 600g bags of satsumas and 75m bags of clementines each year.

Supermarkets have been criticised for contributing to the UK’s food waste mountain by sticking rigidly to quality specifications, and routinely rejecting “ugly” or mis-shapen, but edible, fruit and vegetables grown by suppliers.

Celebrity chefs Jamie Oliver and Hugh Fearnley-Whittingstall have helped drive a campaign to encourage consumers to be less obsessed with perfection, and for supermarkets to relax their rules to sell more “wonky” carrots and other odd-looking vegetables and fruit.

Last month, Tesco announced plans to join forces with suppliers to tackle global food waste. It has widened other quality specifications to take more of farmers’ crops, most recently with British-grown apples.

The changeable weather in Spain has been a challenge for supermarkets stocking salads and vegetables out of season in the UK. Earlier this year they were forced to ration lettuce and courgettes after snowstorms in Spain ravaged crops.

Rebecca Smithers

This article first appeared on the Guardian

edie is part of the Guardian Environment Network

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