Putting A Trace On Greens

Blockchain is known as the technology behind the hip but sometimes confounding digital-only currency Bitcoin. But soon, a blockchain may be linking up to U.S. and Canadian farms.

By Boyce Upholt | Photos By ©

Walmart has asked its direct suppliers of lettuce, spinach and other leafy greens to join a blockchain database by the end of January 2019. At the end of September, those suppliers will need to work with farmers so that each shipment of greens can be traced back to its start.

Blockchain is a novel form of recordkeeping in which each person who handles a product logs an entry into a database, thereby storing a complete transactional history. It’s named for its approach to security: Information is mathematically “chained” together into “blocks,” which become difficult to alter. To develop the new system, the use of which is planned for other products as well, Walmart has been working with information technology company IBM, in collaboration with other food companies, for nearly two years.

“Consumers deserve for us to create a supply chain that is just as sophisticated as our operations,” says Walmart spokesperson Molly Blakeman. “This use of blockchain does that.”

Leafy greens have been targeted due to high-profile outbreaks and recalls. Last spring, when some lettuce bags were tainted with E. coli, Walmart discarded all of its romaine.

In addition to others in the supply chain, the crisis impacted many lettuce farmers who had no way to differentiate themselves as safe. The new system, called IBM Food Trust, will allow a single box of produce on a store shelf to be traced back to a farm in seconds—saving money for farmers and vendors, and potentially saving lives.