Why One Bad Apple

Spoils the Whole Lot

Apples, like many other fruit, produce a natural hormone called "ethylene" as they ripen.  Ethylene is a "starting hormone signal", which means it promotes other fruit near it to begin ripening.

The old saying "one bad apple spoils the whole bushel" is true, because damaged or diseased apples produce high levels of ethylene, which stimulates other apples to ripen too quickly.  As the fruits ripen, they become more susceptible to disease.

Ethylene "producers" should not be stored with fruits, vegetables, or flowers that are sensitive to it.  The result could be loss of quality, reduced shelf life, and specific symptoms of injury. Some examples of ethylene effects include:

• russet spotting of lettuce along the midrib of the leaves;
• loss of green color in snap beans;
• increased toughness in turnips and asparagus spears;
• bitterness in carrots and parsnips;
• yellowing and abscission of leaves in broccoli, cabbage, Chinese cabbage, and cauliflower;
• accelerated softening of cucumbers, acorn and summer squash;
• softening and development of off-flavor in watermelons;
• browning and discoloration in eggplant pulp and seed;
• discoloration and off-flavor in sweet potatoes;
• sprouting of potatoes;
• increased ripening and softening of mature green tomatoes (8); and
• shattering of raspberries and blackberries (2).

Ethylene producers include:

• apples, apricots, avocados, ripening bananas, cantaloupes, honeydew melons, ripe kiwifruit, nectarines, papayas, passionfruit, peaches, pears, persimmons, plantains, plums, prunes, quinces, and tomatoes (14).

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