Apples talk to each other. Eavesdropping can save millions from the trash bin

Tracking apples.
Tracking apples.
Image: Reuters/Brendan McDermid
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One bad apple can, in fact, spoil the bunch.

For that reason, a new startup in Philadelphia called Strella Biotechnology has developed a tool that monitors the fruit on a biological level, making it possible to predict how much time it has on the market before it goes bad.

The company does this by placing small sensor boxes near stored produce. Those sensors tap into the conversations that apples have with one another. It can be difficult to detect, but when it’s time to ripen, apples produce a gas called ethylene. Heightened ethylene levels signal to surrounding apples that it’s also time for them to ripen.

In nature, this type of communication is important. In the process of ripening, fruit often changes colors, emits aromas, and adopts flavors that make it more attractive for animals to eat. That, in turn, increases the likelihood that the plant’s seeds will be dispersed, allowing new plants to take root, grow, and proliferate.

But in the food supply chain, an early signal to ripen can be disastrous, leading to millions of dollars in wasted food every year, says Katherine Sizov, founder and CEO of Strella.

Sizov first learned some of the staggering statistics around food waste while studying neuroscience at the University of Pennsylvania. According to the US Department of Agriculture, some 30% to 40% of food in the US is wasted each year—amounting to more than 218 pounds per person.

“I immediately walked to my grocery because this is such a ridiculous number, and I started asking, ‘Why do you have so much loss?'” Sizov says.

No one could answer her question, so she moved a step up the food supply chain, talking with people who work in big distribution centers where apples and other produce items are stored after being picked.

If stored at the right temperature, a picked apple can last six months or more in storage before it ripens. Apple growers store millions of them in giant warehouses for months, shipping them to retailers as needed. However, apples are hardwired to begin ripening if they are damaged. A cut or a bad bruise can trigger the production of more ethylene—and when neighboring apples detect the gas in the air, they start ripening, too. Once they ripen, apples have a shelf life of just a week or two.

Strella’s sensors dispatch color-coded information to the companies that store produce. Green indicates that a batch of apples have about two months left before they start to ripen. Yellow means one to two months. And red means the apples need to be moved to retailers for consumers within 30 days.

Other technology does exist for detecting ethylene emitted by plants. A company called C2Sense also has a product that detects ethylene levels. Developed in the chemistry department at MIT, the technology behind C2Sense has gotten buy-in from at least one paying customer, AgroFresh, and can be used to detect more than just ethylene: The product can also track levels of ammonium in the chicken industry. The tech gives real-time data streamed directly to AgroFresh.

But few ethylene sensors have worked well commercially because the levels coming from food within the supply chain are subtle and tough to track, Sizov says.

Strella did a trial with a company last year on a room filled with honey crisp apples. The packer wanted to keep the fruit until July, when apple sales often spike. But the sensors indicated he would have to get rid of the apples months before, saving him more than $450,000 in waste, Sizov says.

The startup—which is close to finishing a funding round of about $3 million—currently charges companies about $4,000 to monitor each room, and estimates that such a set up will save an average of about $120,000 in produce per room each year. Lots of produce creates ethylene, Sizov says, and the company will be expanding accordingly. Next up: avocados.