Burger still prime after 14 years in cupboard

David Whipple's 14-year-old McDonald's burger looks as good as new with no mould or any apparent difference from a freshly made burger. Photo / Supplied

An American man has shown off a 14-year-old McDonald's hamburger that looks the same as the day he bought it.

David Whipple, from Utah, had originally planned to keep the burger for two months to show friends how its preservatives would maintain its appearance.

But, after accidentally leaving it in his pocket for two years, Mr Whipple decided to keep the burger for even longer to see how long it could continue looking normal.

Mr Whipple told US television show The Doctors: "I was showing some people how enzymes work and I thought a hamburger would be a good idea. And I used it for a month and then forgot about it.

"It ended up in a paper sack in the original sack with the receipt in my coat tossed in the back of my truck and it sat there for, I don't know, two or three months."

However, Mr Whipple's experiment was then forgotten after the coat was tossed in a closet.

"My wife didn't discover it until at least a year or two after that. And we pulled it out and said, 'oh my gosh, I can't believe it looks the same way'."

Doctors on the CBS show noted that aside from the pickle disintegrating, the burger showed no signs of mould, fungus or even a strange smell.

Mr Whipple said he had put the burger on eBay at one point.

But, despite bids reaching close to US$2000 ($2344), the family decided to keep it for educational use.

He now uses the burger to convince his grandchildren not to eat junk food.

"It's great for the grandkids to see. To see what happens with fast food."