WENATCHEE VALLEY, Wash. — Katherine Sizov crouched down and gently placed one of her sensors in a corner of a cavernous warehouse room that was packed to the ceiling with crates of apples.
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Climate Visionaries highlights brilliant people around the world who are working to find climate solutions.
Forklifts carrying crates sped through the passageway outside. Trucks rumbled up to the warehouse, piled high with Ambrosias, Cosmic Crisps, Enterprises and all the bounty of Washington state’s densely planted orchards. A powerful fragrance hung in the air, mixing with the chill of the refrigerated rooms.
For the next eight months, the device she built — about half the size of a shoe box — was going to keep watch over the 5 million pieces of fruit jammed into that single room, making sure they didn’t overripen during their long stay in suspended animation. As a junior in college, Sizov started a company, Strella Biotechnology, to try to reduce waste in the U.S. food system — a problem that by some estimates creates as much emissions as 33 million passenger vehicles. Now, three years later, Sizov had talked her way into the warehouses of most of the country’s biggest apple producers, and her devices monitor about 15 percent of the entire U.S. crop.
Every fall, apple growers gather billions of apples, rush them into storage, seal the airtight doors and wait until harvest is a distant memory to reopen them. But every spring and summer, there are bad surprises when they slide open their massive warehouse doors only to discover that temperamental Honeycrisps have turned to mush.
Already, agriculture contributes more to greenhouse gas emissions than the total of all the cars, planes, trains and trucks in the world. The pressure to grow more food is leading to deforestation in the Amazon, the drying up of rivers and a greater demand for fossil fuel-based fertilizer. Anything that can be done to reduce waste and increase the productivity of existing agricultural land is a big win for the climate.
Sizov, 24, wants to eliminate food waste one fruit at a time. In central Washington, it was an effort that required almost as much quick footwork as the épée squad she captained as a championship fencer in college. One moment, she was trying to beam the sensor’s WiFi signal through the reception black hole of millions of apples, which cause transmission issues because of their high water content. The next, she was sitting down with laconic apple growers with orchards planted generations ago, trying to convince them she could help them avoid wasted fruit. By day’s end, she might be folding her 6-foot frame into the passenger seat of a rental car, balancing her laptop on her knees and trying to win over Silicon Valley investors on Zoom calls using skills she had picked up partly by watching YouTube tutorials.
“These people wouldn’t normally sit in a room with each other,” Sizov said. “But they all agree that we shouldn’t be throwing away apples.”
When Sizov was growing up near Boston and, later, Alexandria, Va., she’d spend every summer at her grandparents’ dacha outside Moscow. Her parents had emigrated in the waning days of the Soviet Union in search of better medical treatment for her older sister, who had leukemia. Katherine was their first U.S.-born child. They sent her back each year so she’d know where she came from.
She could play along then-rutted roads near Sergiev Posad, an ancient monastery town about 40 miles outside Moscow. The church bells pealed over the winding streets below. From the stove came the sizzling of her grandmother’s doily-like blini, the sour cream-filled pancakes that Russian grandmothers cook as a testament of love for their grandchildren. They’d eat squash and cucumbers from their garden, while apples came from the neighbors’ trees next door. There wasn’t any food to waste because they ate everything that grew.
In the United States, she noticed, there was less of a direct relationship between the food on the tree and the food on the table.
In college, Sizov said, “I kind of realized, I don’t know where most of the food I eat comes from. I thought it came from the grocery store.”
But as she surfed the Internet, searching for topics for the PhD in neurogenetics she expected she would do, Sizov chanced upon a website that described the climate impact of food waste — up to 4 percent of U.S. greenhouse gas emissions, according to analyses from ReFed, a nonprofit organization that works to reduce food waste.
She was captivated. The problem will only intensify as the global population grows, experts say. By 2050, the United Nations expects there will be another 2 billion mouths to feed around the world, an increase of more than 25 percent in just three decades. And as countries such as China and India grow richer, their populations are gradually changing their eating habits: more meat, more eggs — and a bigger carbon footprint tied to raising all of those animals and clearing off land to grow more food.
“If you reduce food loss and waste by 50 percent, you can save a lot of production emissions, but you can also avoid a heck of a lot of deforestation,” said Tim Searchinger, a senior research scholar at Princeton University’s Center for Policy Research on Energy and the Environment. Searchinger explained that after accounting for the fact that an acre of farmland could otherwise be an acre of forest, the carbon footprint of food skyrockets as trees soak up so much carbon dioxide.
Eliminating waste also happens to be a way to help farmers and grocery stores earn more money, since the more efficiently food makes it to consumers, the more cash ends up with the people who’ve done the selling.
That’s Sizov’s sweet spot, she said: If she can convince her clients that eliminating food waste is profitable, the effort will spread far more quickly than if she is simply asking them to be greener out of the kindness of their hearts.
“The pulls of reducing food waste are good for everybody,” she said. “There’s a direct alignment of a sustainable goal with a profitability incentive.”
Like humans, apples breathe in oxygen and exhale carbon dioxide. Putting harvested fruit in special oxygen-starved rooms sends them into a deep slumber that slows their aging. The practice keeps Granny Smiths on grocery store shelves even in June, when the previous year’s harvest is long gone and the new year’s crop is still sweetening on the branch.
But it is hard to keep watch over the fruit while it is slumbering, since opening up the storage rooms would send in a rush of oxygen and speed the apples’ aging. And it’s hard to get the mix of oxygen just right: Too little oxygen and the fruit starts to decompose.
“It’s like being a fruit anesthesiologist. You want to keep it knocked out, but you don’t want to kill it,” said Glade Brosi, a handlebar-mustached tree fruit agronomist at agricultural technology firm Wilbur-Ellis, who was walking through an apple orchard with Sizov on a recent crisp morning.
They weren’t far from the warehouses where she had been setting up her sensors. The fruit growing on the trees was full of promise. The fruit rotting on the ground was emblematic of the problem.
Barren desert mountains towered above. Down a long slope, the Columbia River guttered below. The orchard didn’t look like the old-fashioned pick-your-own places parents take their kids on fall weekends. A generation ago, apple trees in commercial orchards were tree-shaped. Now they grow on trellises, in dense formations that create a “fruiting wall” — a flat surface of dense fruit that receives uniform sunlight and is easier to harvest.
The shift in techniques makes it possible to grow a lot more apples. And it’s possible to keep them fresh for longer, too, with a spray of 1-methylcyclopropene, slowing their ripening for months. If you’ve bought a conventionally grown apple in July at an American grocery store in the past decade or two, chances are it’s been treated with the stuff.
Sizov reached up to a tree and plucked off an apple. It was fat and red, blushing into pink. It looked delicious. She bit into it — and made a face. It was still heavy on starch, far from being ripe.
“This one needs a few months,” she said. It would be perfect next summer, after a long stretch of slow ripening inside the warehouse.
And that’s where Strella’s sensors come in. They monitor ethylene, a gas key to the ripening of fruits and vegetables. Apples accelerate their production of ethylene as they grow sweeter inside the storerooms. Once they’re ready, the gas levels off, telling Strella’s monitors that they’re ready to be sent to supermarkets. Wait too long and the apples turn brown or grow mealy. If producers are lucky, they can try to break even by turning those apples into juice or applesauce. If they’re unlucky, the overripe apples end up in compost or landfills.
Though apples are still harvested by hand, their path to grocery shelves is fairly high-tech. Drones can help growers make decisions about when to gather the apples. The plants where apples are sorted and bagged can take a dozen photos of a single apple to determine its size, quality and eventual destination. It’s all automated on conveyor belts that look like something out of Dr. Seuss.
But storing the apples in warehouses, a crucial part of the process, remains a black box. Without sensors, warehouse workers might try to reach in — gingerly, since a single breath of the deoxygenated air could make them pass out — and grab some apples to check them. But that’s not always effective, people in the industry say.
Watching the evolution of the ethylene levels inside the storehouses gives another portal into the warehouse room.
“There’s been a bottleneck around ethylene,” said Jay Jordan, who worked in the agricultural division of the Dupont chemicals giant before he co-founded Strella with Sizov.
Out of every five apples stored in a warehouse, one typically doesn’t make it to the supermarket. Others make it to the shelves but have lost their crunch by the time consumers bite into them. Extreme weather makes predicting the life of the fruit even trickier: Temperatures in central Washington surpassed 110 degrees for days this summer, making the skin of the apples feel like hot coffee in a paper cup and shaking up their growth cycle.
The more information apple producers have, the better, many of them say. Sizov’s sensors can help them when they’re unsure about storing their fruit.
“Last year I did some rooms, and I had some Gala rooms that it accurately predicted had some problems, and I didn’t want to believe it,” said Leighton Rice, the quality manager at Rice Fruit, a family company in Pennsylvania that uses Sizov’s sensors.
“But when I opened it up, sure enough, there were a lot of problems. That was approaching a million dollars in losses that could have been avoided,” he said.
Not everyone thinks ethylene sensors are the best solution to avoiding wasted apples. Ethylene has a long history of failed technology with big promises but failed potential.
“There’s three different factors to control the loss or waste or decay, and it’s temperature, temperature, temperature,” said Irwin Donis-Gonzalez, an expert on post-harvest technology at the University of California at Davis. He said drawing a straight line between ethylene measurements and fruit ripeness isn’t easy.
Still, food waste experts say, anything that can help food get all the way to people’s stomachs is for the better.
“This is absolutely a solvable problem, and it’s not rocket science. A lot of it is common sense,” said Dana Gunders, the executive director of ReFed, the anti-food waste group. “Today we produce a lot more food than we need. And we use a lot more land than we need.”
She says American culture around food needs to change.
“If I were to walk down the street and I threw half a sandwich on the sidewalk, you would think I was crazy” because littering is taboo, she said. “But if I put half a sandwich in the garbage, you wouldn’t think much of it.”
For Sizov, who designed the sensors along with other undergraduates at the University of Pennsylvania, building new devices is the culmination of a childhood filled with tinkering.
Her father, Konstantin Sizov, trained as an engineer in the Soviet Union. He passed those habits to his daughter, teaching her techniques at an early age. When they lived near Cambridge, Harvard upgraded its chemical laboratories and set out the old equipment for anyone to take. Young Katherine and her father went dumpster diving there. Later, as a student at the competitive Thomas Jefferson High School for Science and Technology in Alexandria, Sizov arranged an internship for herself at the National Institutes of Health.
Spending summers in Russia “expanded her horizons, that there are different ways to do things,” Konstantin Sizov said while sitting on the National Mall one summer evening, the symbols of American power arrayed in front of him.
“Americans generally have a narrow mind-set” about how the world can work, he said, especially since most haven’t lived through the transition from one political system to another.
He said he urged his children to take advantage of living in the United States.
“Use the best of America. You are not here for the social services,” he said he told them. “But this is the number-one place for business and the number-one place for stand-up comedy. So use it.”
When Katherine Sizov arrived as an undergraduate at the University of Pennsylvania in 2015, she didn’t have much food of her own to waste. Her budget was $20 a week. Her meal plan consisted of packages of ramen.
“Then I discovered food stamps, which was really life-changing, finally being able to buy a meal,” she said.
In college, Sizov quickly fell in with a crowd that was experimenting with businesses. After she got interested in food waste, she researched the production chain and decided that, with her background, monitoring ethylene was a good place to start.
Although she couldn’t afford lab equipment of her own, she could sometimes grab time in university labs in the wee hours of the morning when others weren’t using the tools. They didn’t have access to lab-grade alcohol to clean their sensors, so instead they used Everclear, the high-proof spirit beloved by college kids looking to get wrecked. Eventually, she says, they found a way they felt they could reliably monitor the gas.
At one start-up competition, “it was a bunch of dudes in suits, and I was really nervous,” she said. “I came in sweats after the gym.”
She won $500. As her idea took flight, the money started growing. Last year, she raised $3.3 million in seed investments. This year, she’s trying for more.
“Climate change in general creates inefficiencies,” Sizov said. “The way we’ve been structuring climate issues is in the form of nonprofits. But Coca-Cola also needs to figure out what to do with waste.”
Her early investors say they’re happy.
“Reducing waste and improving efficiency in the food supply chain is a goal with purpose,” one prominent venture investor, Mark Cuban, wrote in an email. “It was actually very simple” to decide to invest in Strella, he said.
As Strella spreads its sensors across the apple industry, it is looking for new horizons. The company is expanding to watch over shipping containers and other spots along the journey from field to supermarket. It has plans to tackle avocados and other produce that frequently goes to waste.
With the stakes so high, even small steps to reduce food waste are crucial, experts say.
“These technical solutions are really important. We have to make it as easy as possible not to waste,” said Searchinger, of Princeton. “The simpler solutions the better, because they’re easier to be adapted.”
At the Wenatchee apple warehouse, Sizov stood up from the sensor she had just activated. Fans roared outside. She checked to make sure it was connected to the Internet. Later, she would be able to log in to Strella’s portal to watch the ethylene levels slowly rise. The big doors were ready to slide closed, and the fruit was ready for its long sleep.
“If we don’t solve this food waste problem now, it will become a lot more expensive later,” Sizov said. “As our climate becomes more volatile, this is going to crop up more and more.”