Fact Sheet and FAQs

We may be partial, but we think fruit ripening is the noblest of all ethylene’s uses. We hope you find our ethylene fact sheet and FAQs helpful and informative.

If there is a question that we have not answered, please contact us and we’ll be glad to help!

Fact Sheet

Ethylene is an important, natural plant hormone.
It regulates the ripening and senescence (aging) of plants. Ethylene is normally produced in small quantities by most fruits and vegetables. However, climacteric fruits, like bananas, avocados and tomatoes create larger amounts of ethylene and this release of ethylene starts several actions like increased respiration, more ethylene production, and changes in color, aroma, and flavor. Fortunately, the onset of this internal ethylene production can be controlled. The ability of fresh produce companies and distribution centers to apply ethylene allows the promotion of predicable ripening times and more uniform ripening…the result is better quality and consumer eating experience.

Ethylene is Generally Recognized as Safe (GRAS)
by the United States Food and Drug Administration (FDA). Given the numerous amounts of food substances, the FDA does not categorize every one. Salt, pepper and vinegar are examples. These, along with ethylene, all are within the category of food substances that, when used for the purposes indicated, in accordance with good manufacturing practice, are regarded by the FDA as generally recognized as safe (GRAS) for such uses.

Calcium Carbide is NOT safe for ripening.
Calcium Carbide is used in some countries as source of acetylene gas, which is an artificial ripening agent. However, acetylene is not nearly as effective for ripening as is ethylene, and acetylene is not a natural plant hormone like ethylene. Also, calcium carbide may contain traces of arsenic and phosphorus, both highly toxic to humans, and so the use of this chemical for ripening is dangerous and illegal in most countries.

Ethylene has been found not harmful or toxic to humans in the concentrations found in ripening rooms (100-150 ppm).
In fact, ethylene was used medically as a anesthetic in concentrations significantly greater than that found in a ripening room. However, ethylene is often targeted as the reason for difficulty in breathing in ripening rooms; what can affect some people is usually either:

  • Carbon Dioxide (CO2,) levels: CO2, is produced by the ripening fruit in the room and levels increase over time, or

  • Oxygen levels: The oxygen in the room when loaded is taken in by the ripening fruit. This sometimes will make breathing in a ripening room difficult.

The increased CO2, and decreased oxygen levels are the main reasons for venting the ripening room.

Ethylene action slows at lower temperatures.
At their minimum temperature levels, fruit is basically inactive and does not respond well to externally supplied ethylene.

Ethylene will penetrate most substances.
In fact, it will permeate through produce cardboard shipping boxes, wood and even concrete walls.

Ethylene is harmful to many fruits, vegetables, and floral items.
While ethylene is invaluable due to its ability to initiate the ripening process in several fruits, it can also be very harmful to many fruits, vegetables, flowers, and plants by accelerating the aging process and decreasing the product quality and shelf life. The degree of damage depends upon the concentration of ethylene, length of exposure time, and product temperature. If ethylene damage is suspected, testing for ethylene levels should be performed (here are some ways to test). This will indicate if one of the steps below should be followed:

  1. Ethylene producing items (such as apples, avocados, bananas, melons, peaches, pears, and tomatoes) should be stored separately from ethylene-sensitive ones (broccoli, cabbage, cauliflower, leafy greens, lettuce, etc.). Also, ethylene is emitted by engines. Propane, diesel, and gasoline powered engines all produce ethylene in amounts large enough to cause damage to the ethylene-sensitive produce items mentioned

  2. Ventilate the storage area, preferably to the outside of the warehouse, on a continuous or regular basis to purge the air of any ethylene

  3. Remove ethylene with ethylene absorbing filters. These have been proven in reducing and maintaining low ethylene levels

Ethylene is explosive at high concentrations.
At 27,000 ppm, just a spark can ignite ethylene and cause a deadly explosion. We have an entire section of our web site devoted to the explosions that can result from excessive ethylene: ethylene explosions. However, when using our products as directed, reaching the explosive level is not possible. The explosive level is about 200 times greater than the level necessary to initiate ripening. Always use our generators in ripening rooms that are 1600 ft3 or larger (45 m3).

Ethylene is used to ‘degreen’ citrus.
This is a natural process that triggers pigment changes: the loss of green peel color by removing the chlorophyll, which allows the orange or yellow to fully cover the entire peel. No loss of flavor is caused; this is merely a continuation of the natural plant process.

 

Frequently Asked Questions - FAQs