Burger King is trying to convince people to buy its Whopper sandwich by showing them how disgusting and mouldy it becomes over time.
That may seem counter-intuitive but the burger chain is attempting to make an important point to customers - products without artificial preservatives go mouldy.
The company announced it had removed artificial preservatives from its Whoppers in more than 200 US restaurants and planned to expand this to all outlets in the country by the end of the year.
The chain also confirmed MSG and high-fructose corn syrup would also no longer be used in its food.
The Whopper in the UK is already free from artificial preservatives.
Read more: Burger King UK launches plant-based Whopper
A time-lapse video showed how gruesome the Whopper became when it was left out for 34 days.
The tagline said: “The beauty of no artificial preservatives.”
Fernando Machado, Burger King Restaurant Brands international global chief marketing officer, added: “At Burger King restaurants, we believe that real food tastes better.
“That’s why we are working hard to remove preservatives, colours and flavours from artificial sources from the food we serve in all countries around the world.”
The new ad campaign could be viewed as a dig towards rival burger chain McDonald’s.
That US fast-food giant has often been criticised for having food that doesn’t disintegrate over time (even years) because it’s so full of artificial preservatives.
McDonald’s hit back in a statement, saying: “In the right environment, our burgers, like most other foods, could decompose.
“But, in order to decompose, you need certain conditions — specifically moisture. Without sufficient moisture — either in the food itself or the environment — bacteria and mould may not grow and therefore, decomposition is unlikely.”