We all know that fruits and vegetables have a shelf life. But what is it that happens to them that causes them to rot?

First of all, fruits and vegetables are still alive when they are fresh. That is why they are so delicious and healthy! Just like the trees, vines, bushes, and stalks they come from, fruits and vegetable respire, which is a fancy word for breathe. Just like we exchange carbon dioxide for oxygen, plants and the fruits they bear exchange oxygen for carbon dioxide. The faster they respire, the faster they will ripen and then rot. Keeping them cold slows down the respiration and warming them up speeds it up. This is why many fruits and vegetables should be kept in the refrigerator. However, cold temperatures will ruin some produce, so read Don’t Spoil Your Dinner – How to Keep Fresh Produce Fresh (link at bottom).

Fruits and vegetables get gas, too! Fruits and veges emit an odorless, colorless gas called ethylene. The detection of ethylene triggers the production of more ethylene. That is why one bad apple really does spoil the barrel! A rotten apple will be emitting a lot of ethylene gas, which will cause the other apples to start emitting the gas, and pretty soon they will all be ripe, and shortly after they will all be rotting! The same thing happens in your fridge or fruit bowl. All fruits and some vegetables have receptors that sense the ethylene gas, and when the receptors are “turned on” by the presence of the gas, they activate production of more ethylene. Some fruits and veges are more susceptible to the presence of ethylene than others.

Damage to fruits and vegetables will also cause decay. Plants are designed to defend themselves from the outside world of microorganisms and predators both large and small. When produce gets ripped, punctured, dented, scratched, or even bruised, it means that cells have been broken and they are now susceptible to bacteria. For this reason, you should avoid damaged fruits and vegetables at the store, and also avoid eating the damaged parts of your produce if it happens at home.