My daughter came to me this morning and asked if she could use the milk in the fridge on her porridge. "The expiry date was yesterday," she said.
"Is it safe to use?" I did as any caring parent who wanted to avoid an early morning trip to the supermarket would do, and answered with "they always build in a safety margin so it will be right to drink" hoping that I wasn't about to subject my daughter to some horrible illness.
The use by and best before dates printed on foods are the responsibility of the food supplier. There are so many variables with how the food is stored that the dates printed on the packaging are naturally very conservative.
That conservative nature leads to a significant amount of food waste.
What we really need is a definitive answer.
It is not surprising that researchers have been working on exactly this issue, and scientists from Singapore have developed an e-nose specifically for the decay of various meats.
The e-nose relies on two components. Firstly, a twenty-segment barcode is placed inside the packaging of the meat. As the meat decays, the various lines on the barcode change colour in reaction to the gases produced.
Each bar is made of a natural sugar embedded on cellulose and loaded with a different type of dye. As the type and concentration of gases are emitted, the various bars change colour.
It would be possible to have a chart that outlined colour combinations of the barcode that you could use as a reference to determine the state of your meat. But that would be clumsy at best.
Enter the second crucial component.
Your smartphone. By using the app developed by the researchers, you simply point your phone's camera at the barcode and it will give you an accurate reading of the decay level of your meat. The app is powered by Artificial Intelligence (AI) and initially chooses from a large library of barcode colours but is also continuing to learn more as it is exposed to more tests. The initial work involved 3,475 barcode images and, just with that sample size, the accuracy of the system was rated at 98.5 per cent. As more barcodes are read from more samples, that accuracy will increase.
The ultimate aim? My daughter working out the freshness of her food? Sure, that is one thing, but the real aim is to reduce food waste across the world. In Australia alone, we waste over seven million tonnes of food each year which costs the economy $20 billion and accounts for more than five per cent of Australia's greenhouse gas emissions. The e-nose focuses on meat but it is a start - and I am sure we will see other technological advances in relation to this ongoing problem.
Tell me if you would trust an e-nose to tell you if food was safe to eat at firstname.lastname@example.org.