The reason McDonald's burgers and fries remain intact for 24 years when hidden in shoeboxes is because McDonald's cooks the burgers completely at high temperatures, which may kill many of the microorganisms that can cause the food to decompose. Meanwhile the food itself or the environment is dry enough that it may not harbor mold bacteria or decompose.

On Sept. 1, a U.S. Internet user uploaded a video showing a grandmother keeping a McDonald's set meal for 24 years. According to media reports, the burger and fries were neither moldy nor rotten.

The report said the bag, which bears an advertisement for NASCAR racing, was purchased in 1996 and was stored in a shoebox for 24 years with its contents intact.

The middle-aged woman said the fries looked as if they were a month old and had not spoiled. The bread wasn't moldy and the meat wasn't rotting.

McDonald's officials said that like most other foods, McDonald's burgers can decompose in the right environment, but if the food itself or the environment is dry enough, it may not harbor mold or bacteria and won't break down.

Donald Schaffner, a professor of food science at Rutgers University, said McDonald's cooking the burger completely at high temperatures may kill many of the microbes that cause food to break down.

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Similar news: Icelandic man buys burger and fries for 5 years and still has no mold

According to foreign media, in 2009, the American fast food When American fast food chain McDonald's pulled out of Iceland in 2009, local residents bought their last burgers and fries that had not yet gone moldy.

When McDonald's pulled out of Iceland in 2009, Icelander Smarason reportedly bought his last burger and fries before it closed on its last day and donated them to the National Museum to document McDonald's history there.

Smarason, 28, was surprised that it might be the world's oldest burger, even though it's 5 1/2 years old.

Smarason said that after three years of complaints, McDonald's returned the food to the museum, but instead of throwing it away, he displayed it in his hotel bar in the capital, Reykjavik. The food appeared to show no signs of rotting, except for a reduced number of fries, which he suspects people ate during their visit, Smaracen added.

People's Daily - Icelandic man who bought burger fries 5 years ago still has no mold or spoilage

Jiangsu Metropolis Daily - McDonald's hamburger fries hidden in shoeboxes for 24 years did not go bad did not grow mold or spoil