The tomato is the edible berry of Solanum lycopersicum, a sprawling member of the nightshade family — botanically a fruit but used the world over as a vegetable. Juicy, acidic and savoury-sweet, it ripens from green to deep red and is eaten raw, roasted, sun-dried and cooked down into the sauces, soups and pastes that anchor cuisines from Italy to Mexico to West Africa.