The romaine lettuce E. coli scare is over, but it's taken consumers a while to toss the vitamin-rich leafy greens in a salad again.  That's a concern for everyone up and down the food supply chain, from growers to grocers. So the food industry is turning to a new technology to help quash the spread of food-borne illness: blockchain.

While it has become a buzzword as the basis of cryptocurrencies such as Bitcoin, blockchain is a 10-year-old technology that's being put to work in the grocery business. It has the capability of identifying the source of a food item suspected in an outbreak faster, food safety experts say. Right now, it can take several weeks to track down where a food item became contaminated. Sometimes, that information is not traceable at all.

Walmart is testing the technology as part of an IBM-led pilot that began last summer. Major food companies including Dole, Driscoll's, Tyson Foods, Unilever and Kroger are also in the program.

Within the next year, with all the large companies already on board, the industry adoption in produce and fresh foods will generally be moving quickly, said Suzanne Livingston, a director in IBM's food trust program. "With every incident, we always look at the devastating results and see what would have been different," she said. "All we need now is more companies."

Blockchain provides a digital record that can't be changed without all the parties agreeing to change it. That can create a secure and quickly accessible record of every step that a food item, say a package of sliced mangoes, has traveled along the way to the consumer's table.

Why it's needed

In addition to potentially saving lives, there are financial incentives to solving the mystery of where food contamination began faster and with more precision. Expensive recalls hurt the entire food industry.

"Food product is guilty until proven innocent," said Frank Yiannas, vice president of food safety for Walmart. He is leading the effort at Walmart and first came to IBM with the concept to apply blockchain to food safety. ,

What's being tried

With the mangoes tracked in a blockchain, it took seconds to find the farm, he said. This year, Walmart has moved beyond the pilot and is using the blockchain platform on two dozen fresh foods in the poultry, produce and dairy aisles. The product is in Walmart stores in North Texas.

"The legal requirement for traceability today is one step up and one step back and it's all on paper, which is outdated for the 21st century," he said. "Farmers, processors and distributors and each segment of food system do it their own way."

The one-step method often works, but it still took several days to find the distributor of melons contaminated with salmonella this week in the Midwest. The romaine lettuce was finally traced to fields in Yuma, Ariz.

Walmart is working with IBM, other retailers and food suppliers to develop a system that uses blockchain technology in the grocery aisles. It would quickly identify the source of outbreaks such as the spring 2018 illnesses and deaths linked to romaine lettuce contaminated with E. coli. Walmart tested the system in 2017 with sliced mangoes.

The future

The customer wants to know more about what they're eating, and the blockchain concept has been proven, but putting it to work widely will take some time, Yiannas said. "We're all wondering what would have happened with the romaine incident if we had it," said Doug Baker, vice president, technology at the Food Marketing Institute.

The whole system gets blamed when something spoils or is contaminated with salmonella or E. coli, or a distribution center fails to store product at the right temperature. "We need to shift this from fault-finding to fact-finding," Yiannas said. "If no one is eating romaine, the entire system loses."