The Patisserie Valerie gelaterias at Spitalfields in East London and Duke of York Square in Chelsea feature a flavour called banana blue. You can’t miss it, but you might want to give it a pass. As someone familiar with blue corn, berries and potatoes but not yet bananas I wanted to know what made the gelato blue before deciding for myself. I asked someone at Valerie, who inspected the package and identified the bluing ingredient as E133 – Brilliant Blue FCF.

E133, a synthetic blue coal tar dye, is certified as a safe food additive by the EU and the US FDA. But ExploreENumbers still lists E133 as one of top 10 E numbers to avoid. It was concerns about allergic reactions and harmful effects linked with Brilliant Blue, especially when consumed in combination with other additives, that led Nestlé Rowntree to halt production of blue Smarties until a natural colour could be found. The reintroduced blue Smarties get their blue from Spirulina, a type of blue-green algae rich in protein, vitamins, minerals, and carotenoids.

So is the world ready for Spirulina gelato? Though it’s hard to say, you must admit it does sound Italian.