Keywords: paper-based electronic gas sensor, sensor tag, NFC, chip

Posted on 19 Jun,2019


Can I eat the cheesecake that just expires today?

There is no production date for the snacks bought on the street. What should I do if it deteriorates?

On such a hot day, will the overnight lobster make me stomachache? But why the food still smells good……

I believe that every foodie has encountered one of these situations. It’s pity to throw the date foods, and fear this kind of foods is harmful to body.

As a result, the research team at Imperial College London has developed a tool that lets you know if food is spoiled by cell phone.

▲These labels have been successfully tested in chicken and fish for laboratory testing.

They made a label called “paper-based electronic gas sensor” (PEGS). This prototype label is primarily made of cellulose paper with a conductive carbon-ink electrode printed on it.

The paper fiber of label can absorb the water vapor released by the food when the label is added to a disposable NFC chip and placed in a food package. The conductivity of the paper will increase if the water solubility exists in the water vapor.

As the conductance increases, the amount of power transferred between the electrodes to the NFC chip decreases, and when the threshold is reached, the chip stops working. We can use the NFC-enabled mobile phone to scan and know immediately if the chip is still working.

If still working, eat. Else throw away.


In fact, there are other methods such as using electromagnetic fields (radio frequency identification/RFID) to check the quality of food. Only by attaching RFID tags to the outside of the article, it is possible to detect whether the food is harmful through radio waves. But the advantage of PEGS research is that it focuses on food spoilage because it only works with spoilage gases and works well at 100% humidity and different room temperatures.

In addition, the cost of a single PEGS label is only 2 cents, so it is cheap and easy to mass-produce, and the label is non-toxic and biodegradable, so don’t worry about its safety.

Currently, the team is developing a label array that allows each label to detect different gases and can be used to detect respiratory diseases or air pollution.

We have suffered from food safety problems for a long time. If everyone in the future can have their own tools to perceive food quality and safety, they can avoid the harm of inferior foods in the early stage.

The label that detects whether the food has deteriorated is just the beginning.