This article is about food advertised as "natural". For food that complies with standards of organic farming, see Organic food. UK blue Smarties, old (top) and new (bottom). Blue Smarties were re-introduced by Nestlé in the UK in February 2008, using a "natural" blue dye derived from the cyanobacterium spirulina rather than synthetic blue dye.[1] Natural food and all-natural food are terms in food