A lot of fruit is thrown out when it gets to its destination because it has perished. This is particularly true in the U.S. and China, which have very strict fruit importation policies. The reason fruits perish on the way to their final destination is because, although they are transported in refrigerated vehicles, their core temperature sometimes isn’t low enough to prevent them from going bad. Crates are often stacked in such a way that fruit in the middle of the refrigerator is actually warmer than on the outside. Taking temperatures at the end of the line from the outer fruit can result in a nasty surprise when the truck gets unloaded.
This is why researchers at Empa are working on a sensor that looks like the fruit it’s tracking. One of their first efforts mimics Braeburn and Jonagold apples. The team X-rayed the apples and a computer algorithm created the average shape and texture of the fruit. They then determined the exact composition of the fruit’s flesh and simulated that using a mixture of water, carbohydrates, and polystyrene. Once the artificial fruit was created using a 3D printer, a temperature sensor was put in the middle of it.
Stored in among the real fruit, this sensor is able to record detailed information about the temperature inside the vehicle. The data from the sensor can tell someone exactly when in the transport process the fruit grew too warm, which is useful for insurance purposes, but doesn’t make it possible to respond to changes in temperature before it is spoiled.
The research team is looking for ways to make the sensor wireless or Bluetooth connectable so that transporters can find out about abnormal temperatures in time to save their shipments.
Initial field tests on the sensors are currently underway, and the researchers are looking for industrial partners to manufacture the sensors. The cost of those sensors is estimated to be less than 50 Swiss Francs ($50 US). Considering the losses that occur when fruits perish en route to their destinations, the sensors are bound to be a sound investment for fruit producers and transporters, particularly if the technology reaches a point where the sensors can warn of high temperatures in time for a transporter to resolve the problem before the cargo spoils.
In addition to Braeburn and Jonagold apples, the team has developed separate sensors for Kent mangoes, oranges, and Cavendish bananas. The research team is currently developing sensors for other fruits as well.