Myth or truth: Is one rotten apple enough to ruin all the others?

You may have heard that one rotten apple has the power to spoil all the others. This statement is often used as a metaphor to explain that a bad person can harm an entire group, but does the comparison make sense? Is it really true that a rotten apple spoils the healthy apples around you?

The answer to this question is yes. Some fruits, such as apples and pears, produce a gaseous hormone called ethylene, which, among other things, is known to be a ripening agent. When you keep the fruits next to each other, the ethylene that each one emits causes the next fruits to ripen faster, and vice versa.

Imagine a very ripe apple, almost rotten. This fruit produces a large amount of ethylene, right? If it is next to other apples not so ripe, the amount of this substance produced by the others will increase which, consequently, will accelerate the process of ripening and even decay.

The same logic can apply to moldy fruits. If they are in contact with other fruits, the mold may pass. Therefore, in such cases you should discard all fruits to avoid ingesting the fungus that causes mold. In both cases, both ripening and moldy, it only takes one spoiled fruit to compromise all the others. And once again your mother was right.