As anyone who has picked oranges can tell you, the fruit doesn’t always taste the same. They differ between trees, seasons and locations. Visit a supermarket, however, and you’ll find row upon row of identical-tasting orange juice, 365 days a year, even when there’s snow outside.

Our globalised food system allows food to be grown anywhere that has the right climate, before it is then picked, packed, shipped and finally trucked to wherever customers want to buy it. To get juice that tastes the same from one week to the next, a company might mix oranges from different farms and harvests to achieve a precise sweet/sour balance. The modern food system gives us access to unprecedented variety, but also, when we prefer it, exceptional sameness.

The downside is that long and convoluted food chains can obscure where produce comes from to the point where diners may not know which fish or animal species they are actually eating.

“That single package of ground beef can be coming from hundreds of different sources,” says Alexis Bateman, the director of the Responsible Supply Chain Lab at the MIT Center for Transportation and Logistics. “In the seafood industry, there’s a lot of actual fraud…so people want to make sure it’s the right fish.”

Recently, people have been realising there is something lacking from their diets: quality information.

High-profile incidents, like a 2013 scandal when cheap horsemeat was discovered in European beef products, have meant that people today are more wary of eating anonymised produce. “Consumers are realising that they are more vulnerable than they knew,” says Bateman. “It doesn’t mean our food systems are less safe than they were before, it is that there is a growing awareness.”

But tracing a product from farm to fridge via middlemen, resellers, mixers and packers can be daunting. Even the food’s end seller may not know where it has come from. “The problem is that…they don’t want to offer that information until they have good visibility of their own supply chain,” says Bateman. “Even if they feel like they have a good grasp of their supply chain and they have good practices, some of them still don’t want to in case something were to happen.”

A snack such as a packaged biscuit might contain 18 different ingredients, each with its own intricate backstory. Right now, with the exception of a few foods (like beef), there is no strong evidence that most people will pay more or buy more of a food if it is fully traceable, says Bateman. “Until there is a clear competitive advantage that consumers will always buy the choice that has more information, companies are not willing to disclose that.”

Bateman says the market is changing, though – for example, her local supermarket now has a fridge segment dedicated to traceable foods, something she never could have imagined two or three years ago. “It’s piecemeal, it’s slow but there is this demand and the consumer-facing companies are getting pressure to act which is pushing it up the supply chain.”

To track an orange’s journey to the Netherlands from Brazil, the juice companies used a tool that most people probably associate with the digital currency bitcoin. Blockchain enables cryptocurrency, but it is also very useful for recording other data, such as what happens to an orange after it gets picked.

In a blockchain, data is bundled together in a series of parcels known as “blocks” that are digitally “chained” together and stored on many computers at once. Each block of data is tightly encrypted so it can’t be changed by anyone further along the process. For bitcoin, the blockchain records digital transactions of money. But the same system is now being adapted to store data about physical items – including food.

“Every piece of data is time stamped,” says Inma Borrella, who coordinates the Blockchain Research Group at the MIT Center for Transportation and Logistics. “It’s not like a database where you can go in and edit data, it just keeps adding continuously. It allows you to keep a record of all the places [a product] passes through and all the different organisations that have touched a product.”

But tracing food brings additional challenges compared with tracking a purely digital product. “When you are talking about a physical item and not a digital asset, you have the additional challenge of getting an accurate translation of the physical world into the digital world,” says Borrella. “It’s about how you make sure the digital record is the truth and not a misrepresentation or even just a human error.”

Food needn’t go the high-tech route to become traceable. In China, tracking food to the source can be as simple as travelling to a farm open day, 70km from Beijing.

Originally a city-dweller, farmer Shi Yan started Shared Harvest farm near Beijing in 2012 and the farm now feeds 1,000 families. Shared Harvest operates on the Community Supported Agriculture (CSA) model, which lets households sign up to receive fruits and vegetables for up to a year, and pay some of the money upfront.

The early payment system means the people eating the food can share some of the risk with the farmer. “For most farmers, they buy seeds and fertilisers for a whole year,” says Shi.

“That’s a long time for a farmer and it’s hard for small farmers to invest that themselves,” she adds. “Because consumers pay upfront they have this ability to invest in what they need. And because there is no middleman we have the right to price our produce. It gives respect to the farmers and they feel more dignity.”

Not only are the households and the farms connected financially, householders can physically visit the farms to make the bond more personal. Visitors to Shared Harvest’s open days can see the 20 hectare land parcel where 30 greenhouses – tended by 50-70 farmers – grow pears, cherries, peaches, and other varieties of fruit and vegetables for delivery in boxes to Beijing homes. Chickens and pigs are reared, too.

“Our consumers know what they eat and how it was produced, so they will also reduce waste,” says Shi. “Some of our members have been eating our vegetables for three, four, five, six years and their kids have grown up eating our produce, so when they come to the farm and visit us, it’s a very different connection. Our farmers feel responsible, too.”

The produce is grown using methods that mix modern knowledge with ancient Chinese practices. “In China, there is more than 5,000 years of farming history but, when you look back, you see that for most of history our ancestors were doing farming that could be called organic or sustainable. They knew how to compost everything and use manure,” says Shi.

The aim of the Shared Harvest project is to take the most sustainable elements of these ancient practices and build on them using information obtained with modern technologies. “From the beginning, we worked with local farmers who are mostly about 50 to 70 years old, and they still remember when they were young and they used very little or no fertiliser or pesticides, so we learn a lot from them,” Shi says. “The difference is, we grow 80 varieties of vegetable in a year, because we use a lot of data from the internet.”

Shi says the risk-sharing model is expanding in China, with more than 1,000 CSA schemes now up and running. And, while she doesn’t want to expand her own farm, she is sharing her knowledge by running farmer training courses. She laughs when she recalls that one trainee farmer arrived for the course equipped with a degree in agricultural machinery, having never driven a tractor. The courses have been popular. “Last year we had 107 new farmers graduate,” she says.