olive oil, fish, milk, grains, honey, coffee and tea, spices, fruit juice, and organic produce. With a list like that, it’s almost harder to name items that aren’t regularly spoofed. If consumers know that they’re likely paying for something that isn’t genuine, they may no longer be willing to fork over top dollar for premium products. On the other hand, if companies made the supply chain more transparent and accessible to their customers—showed them where their food came from and where it has been—perhaps consumer trust would be restored.

A second problem that plagues the industry is food fraud. Commonly faked, diluted, or adulterated foods include

Since 2016, Walmart has been working with IBM to develop software that uses the blockchain to track products through its supply chain, from the farm to the consumer, in the hopes of addressing those issues. If only those heads of romaine lettuce that Canadian officials thought caused the early winter outbreak had been tracked on the blockchain, the thinking goes, then government agencies and retailers would know where they had come from, and where they were sold, and the contamination could have been contained. Walmart’s vice president of food safety, Frank Yiannas, has called the technology “the holy grail.”

When used as the backbone of a digital currency, as with Bitcoin, one can see not only who has what now, but who had what a week ago, or a year ago, because the ledger is a complete history of that currency. However, as soon as you use the blockchain to record the movements of something that cannot be digitized—a banana, for example—it creates a point of failure.

Last year, Yiannas asked his team to trace a package of sliced mangoes back to their source. He says it took them six days, 18 hours, and 26 minutes. After Walmart used the software developed with IBM to track mangoes from a farm in Mexico to U.S. stores over a 30-day period, the same exercise took a mere 2.2 seconds.

NFE

The mango pilot is one of two that Walmart and IBM have run, and one of the largest proofs of concept within the industry to date, involving 16 farms, two packing houses, three brokers, two import warehouses, and one processing facility. Over the 30-day period, they captured 23 different lot codes and tens of thousands of sliced mangoes. In China, the company tracked several different pork products from a single supplier to stores.

Not everyone finds the company’s work with blockchain to date very impressive. Mitchell Weinberg, who founded the food fraud detection and prevention firm Inscatech, thinks it unrealistic to believe all of the food we consume can be tracked on the blockchain. “If they’re selling a bottle of spices, let’s say, I would challenge them to say which plant that particular herb or spice came from,” he says.

Yiannas acknowledges that tracking the five or 10—or more—ingredients that can go into a single product is a complex undertaking, but also reiterates what an accomplishment it is to track even a single ingredient. “Again, because it’s a fragmented food system—lots of paperwork, not digitized—so the idea of doing it in 2.2 seconds because it’s all recorded digitally is just fascinating, mind-boggling,” he says.

“To your point with the multiple ingredients,” Yiannas adds, “It becomes harder but it can be done. So, basically what you could do is you track back that the pizza was manufactured at a facility, and then you can track back all the ingredients that went into that pizza and where they originated from. But it adds a layer of complexity that would be very hard to do on paper.”