This is not your average middle school "invention convention" or science fair, this is a high stakes compeition, hosted by lego, with a $250,000 prize. The "Global Innovation Awards", as they are called, feature groups of 9-16 year olds, who are tasked with inventing around a central theme - this year, food safety. The idea is to encourage future inventors, and to teach patenting and protoyping of their creations.
One of the finalists in this years competition has the potential to prevent millions from consuming spoiled meat and eggs. The "Erasable Barcode" was submitted by a team from a middle school in Ohio, and identifiies when meat has been stored at an improper temperature, theoretically preventing it from being sold or consumed. When the barcode is activated, the word "safe" appears. As the product sits out at too high a temperature (usually above 40-50 degrees), the ink will slip down, covering the barcode. The top then reads, "unsafe."
All of the runners-up also deal with food temperature - a smart-label that changes color when something has gone bad, a FreezeStick, which keeps food colder longer, and my personal favorite, the Smart Milk Pitcher, which detects the pH of the milk and lets you know if it spoils.
Innovation in Food Safety From Kids, With An Assist From Lego from FastCo Exist