It is the world’s favourite chocolate spread, but a tweak to the Nutella recipe has sent fans a little nuts.

A sharp-eyed German consumer group first noticed the change, revealing that Nutella now contains 8.7 per cent powdered skimmed milk, compared to 7.5 per cent before.

The Hamburg Consumer Protection Centre also pointed out that the sticky spread now has more sugar in it – up from 55.9 per cent to 56.3 per cent.

The watchdog added: “As the colour of the new Nutella is lighter, we are working on the assumption that skimmed milk powder was added at the expense of cacao.”

Ferrero, the Italian company that makes Nutella, confirmed the changes but assured customers that they would notice no difference to the taste and quality of the product. The firm said that other food companies frequently made similar modifications to their products.

“The quality, the sourcing and all other aspects of Nutella ingredients remain the same,” Ferrero said. "The ingredients list is, as usual, displayed on the jar and on the Nutella webpage. All relevant aspects, from a diet perspective, are the same.”

But that was of little reassurance to some Nutella aficionados, who expressed their irritation on social media. Some even proposed a boycott of the spread.