The saying that "one rotten apple spoils the bunch" is typically used as a metaphor to describe how one person with a bad attitude or dissenting opinion can turn others to his/her side. Also more recently, the phrase "Bad Apple" pops up in reference to Apple the company (as anyone who's ever been embarrassed by the auto-correct feature will tell you), but is there any truth to the original saying?

  • Has scientific evidence ever shown whether or not the addition of one already rotting apple is likely to ruin others in a given container?
  • I doubt a thing obvious like this got any scientific coverage. "Rotten" is caused by multiplying living cultures. Infecting the bunch results in spoiling it.
    – Suma
    Jul 12 '11 at 0:30
  • @Suma That's what I thought, especially in a moist, enclosed environment, such as a bag. However, it would still be interesting to see what came up if people actually studied this. Jul 12 '11 at 0:36

YES, one rotten apple can spoil the bunch, due to the release of ethylene.

From Education.com:

The fruits themselves are producers of ethylene which is a ripening agent.

Fruits will remain fresh and firm until the concentration of ethylene surrounding them becomes high enough to stimulate further ripening.

Many fruits are shipped when they are not fully ripe and then sprayed with ethylene gas on arrival.

From the Botanical Society of America:

In general, plant tissues communicate using classes of compounds called hormones.

These are defined as substances produced in one location that have an effect on target cells in a non-adjacent location.

In plants, germination, growth, development, reproduction, and environmental response are all coordinated through hormones.

Although most of the main plant hormones are transported in the vascular system of the plant, one class of hormones is transferred in gaseous phase. This class includes the plant hormone ethylene.

Ethylene promotes fruit ripening.
Apple growers take advantage of this by picking fruit when it is not ripe, holding it in enclosed conditions without ethylene, and exposing it to ethylene right before taking it to market.

This process is why we have newly ripened apples grown in temperate North America even in the spring and summer (apples ripen in the fall).

From the British Columbia Ministry of Agriculture:

Ethylene is considered to be a plant hormone, a growth regulator ... It has sometimes been called the death hormone, because it promotes the aging and ripening of many fruits and flowers.

Ethylene evolves naturally from plant materials that are aging, ripening or rotting.

From NEWTON, Ask a Scientist:

The goal of a fruit is to spread its seed, so it needs to rot in order to get the seeds out of the fruit. There are actually hormones, especially ethylene oxide that promote fruit ripening.

If you want to get a piece of fruit to ripen, put it in a bag with an apple which generates a lot of ethylene oxide.


  • 1
    Nicely done (as always). I had read something similar with regard to bananas, and wondered if the same mechanism may or may not have given rise to that particular expression. Jul 12 '11 at 20:28

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