Outbreaks of food poisoning due to bacteria are all too common today. In November and December of 2017, for instance, an outbreak of Shiga toxin-producing E.coli – the deadliest strain of the bacterium – caused more than 60 people in the United States and Canada to fall ill. Two of them died. And although Canadian officials pointed to romaine lettuce, the Centers for Disease Control and Prevention (CDC) was unable to definitively identify the source of the contamination—saying only that “leafy greens” were likely the source.

According to CDC estimates, foodborne illnesses cause nearly 28 million to fall ill every year. A lot of the time, the problem could have easily been prevented. But because it often takes too long to designate a product recall, or to isolate contamination on the supply chain, health officials don’t realize there’s a problem until it’s too late.

Enter blockchain.

Theoretically, blockchain gives us the ability to trace a single leaf of lettuce from a specific field, to the truck it was transported in, to the factories that process it, all the way to the warehouse and eventually the grocery shelf.  Instead of taking two weeks to track food from the farm to the store to a restaurant, a blockchain track- and- trace solution happens in seconds.

Say a restaurant discovers its vegetables are contaminated. With a blockchain-powered track and-trace solution, the vegetable shipment can be traced via serial number back to the distributor and original supplier. The supplier can be tagged quickly, and anyone who has bought the vegetables can be warned.

Last year, Walmart and nine other companies started working with a technology partner to create a blockchain for tracking food this way, through the global supply chain.

It all started with a package of sliced mangoes. Before implementing the track-and-trace technology, Walmart said it took the company six days, 18 hours, and 26 minutes to track it back to its origins. When Walmart used the software, it was able to track the mangoes from a farm in Mexico to U.S. stores over a 30-day period in an astonishing 2.2 seconds. The difference between 2.2 seconds and nearly seven full days? A lot fewer people getting sick from contaminated food.

It’s one thing when blockchain helps companies manage their operations, but when we see how the technology can be used on a supply chain to potentially prevent disease – and possibly even death – we open our eyes to all the problems the technology can solve. A world where we can eat mangoes without fear is a good world, indeed.