The internet has been reminding us regularly of late that small, plain McDonald's burgers don't rot if you leave them out. The standard conclusions people draw from this are obvious. Lopez-Alt decided to test that hypothesis by comparing the (lack of) decomposition of a McD's burger with a home-ground burger using 9 different samples and trials. The costs of science included sleeping on the sofa for over two weeks after debating the wisdom of this particular trial
The results are in and a home-ground burger of the same size also doesn't rot.
If you leave out the salt, it still doesn't rot.
If you make it bigger, then it rots.
The issue is that when the burger is small enough, the moisture evaporates from it before the mold has a chance to grow. Quarter pounders, whether home-ground or McDonald's style, do rot. And if you put the smaller burger in a sealable plastic bag so that the moisture can't escape ... it rots.
So stop picking on the poor, helpless multi-billion dollar corporation, or at least stick to scientifically accurate outrage. McDonald's deserves a break today.