Dive Brief:
- Walmart unveiled a blockchain-backed traceability system for leafy greens yesterday in a letter to suppliers. Participation in the program will be mandatory for all suppliers of lettuce and leafy greens in 2019.
- The retailer has been developing and piloting the system for 18 months with the IBM Food Trust network. Walmart said the system will reduce the time it takes to trace a package of lettuce back to the exact farm from days or weeks, to seconds.
- "Our direct suppliers are required to conform to one-step back traceability on the blockchain network by Jan. 31, 2019 ... thereafter, our suppliers are expected to work within their vertical systems or with their suppliers to enable end-to-end traceability back to farm by September 30, 2019," reads the letter.
Dive Insight:
Walmart is turning to blockchain to trace leafy greens, an increasingly common move for any industry that needs to increase visibility from coffee to shipping containers.
"Suppliers will be required to capture digital, end-to-end traceability event information using the IBM Food Trust network," according to the company. The letter to suppliers describes the software as both user-friendly and low-cost.
"There are some really helpful on-boarding programs suppliers can take part in through IBM. Think about when you get a new iPhone – the instructions are easy to understand and you’re quickly up and running. That’s the aim here. Essentially, suppliers will need a smart device and internet to participate," Walmart spokesperson Molly Blakeman told Supply Chain Dive.
But Sarah Taber, an independent food safety consultant who performs food safety audits on farms across the country, is skeptical that blockchain is the answer to food safety fears — especially when it comes to prevention.
"You can fabricate blockchain just as easy as anything else. It's treated like a guarantee and it's just not. It's just a ledger where you keep entries. People get excited about blockchain because it is fantastic for tracking digital assets, but for physical assets, it's just not," said Taber, who says that no digital system can compensate for subpar controls in the field and up the supply chain.
"From running hundreds of mock recalls in person, I know that in the vast majority of cases when something gets lost it was just disorganization and confusion. Throwing another tool on the pile isn't going to fix that. The only solution to that is training, which requires investing in people and creating space for your supply chain to invest in people," Taber told Supply Chain Dive.
"You can fabricate blockchain just as easy as anything else. It's treated like a guarantee and it's just not."
Sarah Taber
Food Safety Consultant
Though Walmart emphatically stipulated in its letter that fresh leafy greens are "overwhelmingly safe," this category of food causes more food-borne illness outbreaks than any other in the U.S. and 2018 has been a particularly deadly year. At least five people died from E. coli exposure from contaminated romaine lettuce this year, according to the Center for Disease Control (CDC), which was consulted for the project along with Dole and other Walmart suppliers.
Walmart already requires its suppliers to pass certain food safety audits, but a major problem when a bacterial outbreak is first suspected is first locating the contaminated food and then finding the source of that particular leaf or head of lettuce. Since some leafy greens are prewashed and mixed into massive batches and then bagged, before being trucked across the country, determining the farm of origin for a single salad is a tall order.
