Nation & World

Using blockchain to track food poisoning

Food traceability 'at the speed of thought'

Chicago Tribune photo: Blockchain, the encrypted accounting platform, may have helped solved the mystery of the romaine lettuce E. coli outbreak.
Chicago Tribune photo: Blockchain, the encrypted accounting platform, may have helped solved the mystery of the romaine lettuce E. coli outbreak.

The first food poisoning cases came to light in late March — eight patrons of fast-food restaurants in New Jersey suffered cramps and diarrhea that sent them rushing to hospitals.

More than two months later, one person is dead in California, 75 others have been hospitalized, and federal authorities still don’t know where a nasty strain of E. coli bacteria latched onto romaine lettuce from Yuma, Ariz.

Their struggle to trace dozens of supply lines across 32 states, on a paper trail that often actually may be on paper, demonstrates the limits of tracing food by methods rooted in another century.

Food safety advocates and industry insiders say it may be time to borrow the encrypted accounting platform that drives cryptocurrency — blockchain.

“I often describe that as food traceability at the speed of thought — as quickly as you can think it, we can know it,” said Frank Yiannas, vice president of food safety for Walmart, which is scaling up an IBM-driven pilot blockchain that already includes top suppliers such as Unilever, Nestle and Danone.

Not long ago, Yiannas, who guards the integrity of food in Walmart’s $280 billion grocery empire, would have brushed off the notion of an instantly “knowable” and verifiable food chain as fantasy. He heard about it two years ago, when Walmart was about to open a food safety institute in China, where 10 years ago a baby formula adulteration scandal sickened 54,000 babies.

“Up until that point I only knew that it was the technology behind bitcoin,” Yiannas said. “I will tell you I was a bit of a skeptic, just like many people are about the technology.”

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Blockchain, for all its cloak-and-dagger associations, is basically a democratized accounting system made possible by advances in data encryption.

Rather than storing proprietary data behind traditional security walls, companies contribute encrypted blocks of data to a “distributed” ledger that can be monitored and verified by each farmer, packer, shipper, distributor, wholesaler and retailer of produce.

No one can make a change without everyone knowing, and agreeing to it.

“If I want to change something or fudge something on my version of the ledger, I then have to share it with everybody else and they all have to agree to that,” Yiannas said. “You can’t have two separate sets of books. It’s one set of books that everyone sees.”

As it stands, no one can see the entire path from farm to fork.

Each time a food-borne illness breaks out — which tends to happen around 900 times a year — investigators have to work their way backward, one link at a time, from victims to fields, tracing multiple paths across separate companies and sometimes across international borders.

“It’s very linear, but the food system as we know is not very linear,” Yiannas said.

That linear approach can cost lives and waste billions of dollars in health care costs, lost work hours and trashed food every year, health officials and analysts say.

Food-borne illnesses can cost the economy $152 billion a year, with tainted produce responsible for a quarter of that damage, according to a Pew Charitable Trust study.

Take mangoes. The increasingly popular fruit grows on small farms scattered across Latin America, and can harbor listeria, a bacterium that kills 260 people per year in the U.S., according to the Centers for Disease Control and Prevention.

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Two years ago, Yiannas told his staff to trace a packet of sliced mango from a Walmart aisle the traditional way.

“I looked at my clock and wrote down the time and date, and I timed them,” he said. “It took them six days, 18 hours and 26 minutes.”

Under a week is considered fast by the current link-by-link method known as “one up, one back” tracking, said Yiannas, who previously headed Walt Disney World’s health and safety program. Walmart has a sophisticated tracking system for its part of the supply line.

Beyond the walls of Walmart’s distribution centers, though, record-keeping can get hazy.

“Believe it or not, it’s still largely done on paper,” Yiannas said. “It’s done many different ways by many different actors.”

It took a month to build the blockchain network, which depends on cooperative partners agreeing on what information to contribute. By then, Yiannas felt confident enough to pull off the test live, at a stockholder meeting last summer.

“It wasn’t staged,” he said. “We had a backup in case the technology failed.”

It worked — they mapped the mango supply line in 2.2 seconds.

The next day, Walmart started contacting suppliers. “I think we’re onto something here,” Yiannas told them.

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