Ethylene Management Breakthroughs

The most recent report from the Food and Agriculture Organization of the United Nations estimates that a staggering 1.3 billion tons of food is wasted globally every year, resulting in direct, annual economic losses of $750 billion U.S. dollars. A projected 40 percent of food goes uneaten just in the U.S., according to the Natural Resources Defense Council.

The significance of these statistics takes on still more meaning when factoring in the environmental and social impacts of global food wastage. Some 3.3 billion tons of greenhouse gases are pumped into the planet’s atmosphere just to produce food that is eventually discarded into landfills, which, incidentally, further emit damaging methane gas. Amidst all of this waste, 870 million world citizens go hungry every day.

What’s responsible? The causes of food waste of course are varied, complex, and prevalent throughout the entire supply chain—overproduction, inadequate storage or packaging, inefficient stock management, consumer confusion about dating labels, and oversized portions to name some.

But there is also one simple culprit hidden within nature that’s responsible for much of the wasted food, yet often overlooked: Ethylene. Ethylene is the naturally occurring gas emitted by many kinds of fruit which acts as a ripening hormone.

For more than 80 years, it’s been known that ethylene is emitted by various kinds of produce when under stress or injured, such as when they are picked, peeled, pressed into packing containers, or bruised in consumers’ grocery bags. This begins occurring immediately upon being harvested, but accelerates as the fruit ages.

Ethylene can be thought of as a distress signal, sent to other fruit and vegetables to warn of imminent danger, and to communicate the need to ripen as fast as possible. The gas is responsible for changes in taste, texture, color, and other ripening processes. Chlorophyll is degraded, new pigments are produced, and the activity of many maturation-related enzymes intensifies. Starches, acids, and lipids convert to sugars while fruit pectins degrade. Consequently, produce items respire, abscise, soften, and grow mold to the point of spoiling—shortening the shelf life.

Slowing Down the Clock

Fortunately, there are certain best practices for managing ethylene exposure that can be used across the supply chain in order to slow the ripening process and reduce instances of premature rot, mold, and waste. Over the past 10 years, society has wised up to the significant impact ethylene can have on fresh produce. As a result, new processes, innovations, and technologies for produce supply chain players have become available that are far more effective at controlling ethylene than ever before.

The gas is responsible for changes in taste, texture, color, and other ripening processes.

For maximum shelf life and quality, certain climacteric fruits and vegetables (produce that rapidly ripen to a climax in response to ethylene) such as apples, mangos, tomatoes, peaches, and bananas should not be stored or shipped with non-climacteric produce like cherries, lemons, oranges, broccoli, or lettuce. In many ways, climacteric and non-climacteric fruits “speak” to one another, with ethylene being the common language. So for example, despite producing comparatively smaller amounts of ethylene on their own, strawberries exposed to more of the gas will take it as a sign to begin ripening more rapidly. Ethylene has a cumulative effect, so continuous exposure to even small amounts of ethylene can result in significantly shortened product lifespan. And overripe or rotting produce continue to emit ethylene, so should be removed promptly.

While most who work inside the production and distribution of fruits and vegetables are accustomed to this segregation of climacteric and non-climacteric produce, this comes as a surprise to most people. After all, in retail settings the majority of produce is stored in a single space and then displayed in close proximity as a convenience and enticement to shoppers.