A McDonald's burger bought in 1995 and kept in an Australian shed for years has never decomposed, according to two men who now refer to the quarter-century Quarter Pounder as their "mate".
Casey Dean, 39, and Eduards Nits, 38, claim they ordered the Quarter Pounder with cheese from a McDonald's outlet in Adelaide as teenagers -- and have hung onto it ever since.
"Being teenagers we ordered a truckload of food, and it was just way too much," Dean told AFP. "It started a chain of events where we were joking 'imagine if we kept this forever', and here we are."
Though the burger has shrunk a little from its original size, its shape remains intact, there are no signs of mould, and it doesn't smell.
"Even the sesame seeds are still on there, just a few have been knocked off," Dean said.
The men say their relationship with the Quarter Pounder will span 25 years by November 2020, a milestone even many marriages fail to reach.
"We have been talking about taking him back to his birthplace, just go see the staff there and see if he recognises anyone," Dean said.
Dubbing it the "Senior Burger" and referring to it repeatedly as their "mate", the men have created social media profiles for the burger and even wrote a song about it.
They believe it is the oldest known McDonald's burger in the world, outranking a prominent decade-old cheeseburger displayed in a glass case in Iceland and live-streamed online to thousands of viewers.
Storage for the ancient Aussie burger has been rather less considered, though it has mostly been kept under lock and key in a box made of timber and cardboard.
That box spent about a decade jumbled up with clothing inside a shed in Adelaide, where temperatures regularly top 30 degrees Celsius in summer.
When they eventually went to check on it, Dean said even rats had turned their noses up at the morsel.
"The rats had actually eaten through the plastic bag, heaps of clothes, got into the box and they'd left the burger," he said.
"Our mate was safe."
Dean said he understood why some might be sceptical about their claim, but argues the old-school packaging -- waxy paper and a cardboard ring -- accurately date the burger to the mid-1990s.
He is steadfast that the pair would never part with it despite fielding offers from around the world when it first came to public attention in 2015.
A McDonald's spokeswoman did not dispute the assertion, saying the question of why some of its burgers did not decay came up "from time to time" but there was a "simple explanation".
"The reason why our burgers sometimes don't go mouldy when left out at room temperature, in a dry environment, is that once the food is cooked there isn't enough moisture to support bacterial growth to break it down," she said.
"Instead, it simply dries out."
She advised the best way to enjoy the firm's food was "when it's hot and tasty".