Elizabeth Weise

USATODAY

Editor's note: ​This story first published Monday Dec. 5, 2016.

SAN FRANCISCO — Amazon is testing a grocery store in downtown Seattle that lets customers walk in, grab food from the shelves and walk out again, without ever having to stand in a checkout line.

Customers tap their cellphones on a turnstile as they walk into the store, which logs them into the store's network and connects to their Amazon account through an app.

The service is called Amazon Go. It uses machine learning, sensors and artificial intelligence to track items customers pick up. These are then added to the virtual cart on their app. If they pick up an item they later decide they don't want, putting it back on the shelf removes it from their cart.

The Seattle-based company calls it, "Just walk out technology."

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When the customer leaves, the app adds up everything the customer has taken and charges their Amazon account.

Amazon said it began to work on the project in 2012. It is currently being tested by Amazon employees at the location at 2131 7th Ave., near Amazon's offices, but will open to the public in early 2017, the company said.

The technology "is amazing," said Phil Lempert, a food marketing expert based in Los Angeles.

He's even more intrigued by the multiple images of "meal kits" show in Amazon's video. These "everything you need to cook a quick, high-quality dinner" kits have become popular, but the economics of delivering them has meant they're difficult to make economically viable. Stores such as Amazon Go may provide a sweet spot for them.

"When you look at the store itself in the video (and presumably it is the actual store), they have done a great job of merchandising, and having "meal kits" available is simply brilliant. As the meal-kit industry struggles due to the shipping/logistics aspect," Amazon Go could be a venue where they could succeed, said Lempert.

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