By Julia Banim & Niamh Kirk The world’s longest-living siblings all hail the delicious soup recipe that has helped them live a long and prosperous life. The Melis siblings, who were named as the world’s oldest siblings in 2012 by the Guinness World Records committee claimed their secret is all down to a simple bowl of nourishing soup – a diet staple to the family. The nine siblings, who had a combined age of 818 years at the time, hailed the dish Sardinia Minestrone and claimed it helped them all to achieve long lives. The oldest sister Consolata Melis celebrated her 105th birthday not long af…