The reason is this

It happens to you that whenever you shop your food carton breaks out of vegetables and fruits? But a few days later, they all become soft and liquid. Use these rules and you will see that you will be away from food breakdown and keep them fresh for too long. Fruits, such as tomatoes, bananas and melons, produce ethylene gas, an ingredient that accelerates the breakdown. Cucumbers are super sensitive to this ingredient, so they need their place away from those fruits mentioned above.