Tesco is trialing the sale of unwashed potatoes for the first time in 40 years in a bid to reduce food wastage. Shoppers at 262 of the supermarket giant's 2,650 stores can now buy spuds as nature intended from the Branston organic range. Experts say potatoes last longer if they are kept dry and in a dark cupboard, as both light and moisture can result in rotting on the skin, which will shorten their shelf life. They should also be somewhere ventilated, rather than in airtight containers. The logic behind selling potatoes with soil is it helps to block out light and slow down decay and could extend usability dates from five days to 11. Customers will not however receive fewer spuds in the bag, as Tesco said it has taken soil into account and adjusted the weights accordingly. Rob Hooper, from Tesco, told The Sunday Times: 'Up until about 50 years ago, potatoes would generally be sold unwashed, and having a natural film of soil around them would help keep them fresher for longer.