FANS OF MCDONALD’S burgers can rest easy tonight.

Recent experiments conducted by website A Hamburger Today show that rot-free burgers are not specific to McDonald’s.

Testimonies posted online about McDonald’s burgers which had not decomposed despite sitting in the open air for a year prompted J Kenji Lopez-Alt to conduct an experiment to prove or disprove the statements.

Teacher Karen Hanrahan posted photos online of a McDonald’s burger she claims to have had for about 14 years, and US artist Sally Davies photographed her Happy Meal burger daily for 137 days.

Neither showed signs of mould or decomposition.

In Lopez-Alt’s tests, regular home-made burgers also failed to show mould or decomposition after being kept for weeks in the open air.

He concluded that salt content had nothing to do with the apparent preservation of the burgers; size did.

Lopez-Alt claims that small burgers become mummified rather than mouldy because they dry out before mould can set in, saying: “the burger doesn’t rot because it’s small size and relatively large surface area help it to lose moisture very fast. Without moisture, there’s no mold or bacterial growth”.

Bigger burgers, on the other hand, will rot if left in conditions where moisture will encourage mould to develop (by being placed in a plastic zip-lock bag, for example).

Lopez-Alt says he didn’t carry out his experiments out of a fondness for McDonald’s: “My problem is not with McDonald’s. My problem is with bad science”.