Detecting whether or not meat inside the plastic wrapping at your supermarket (or in your fridge) is still good could soon be much simpler with a clever sensor that changes color in the presence of rotten food.
Vacuum-packing of meat products is a great 20th Century innovation–it presents the meat so consumers can see what they’re buying, enables easy handling in the distribution network and supermarket, and can act as an airtight barrier to aid in the preservation of the food inside. There’s just one flaw: The wrapping is so effective that it’s impossible to detect, on purchase, if the meat’s been mishandled (or if it’s been in your fridge for too long) and gone bad. The only thing you have to go on is the best before date–and your nose when you finally unwrap it to cook it. Which is exactly the task that a new visual sensor developed in Germany aims to tackle.
Research at the Fraunhofer Institution in Munich has resulted in a polymer film that changes color to a bright blue from a bright yellow when the meat inside the wrapping has gone bad–meaning it’s not suitable for eating due to potential health risks from bacteria. The film is sensitive to biogenic amines, molecules that are liberated when fish of meat goes bad–they’re the same chemicals that give rotten meat its distinctive smell (something we’ve evolved to detect, with that stomach-churning reaction).
The product is cheap and easily incorporated into standard packaging, meaning it adds significant value to the packaging from a consumer and food-safety point of view without significantly adding to the cost of packing a food product (which would otherwise be a barrier to adopting such a system).
The team has also developed an electronic version that could be used in the food production industry itself–it’s more expensive, but much more sensitive to the presence of amines, giving production line management a more accurate feeling for how well their food handling procedures are working, and how different meat products should be given different expiration dates. Considering the number of folks who suffer from bad-meat food poisoning each year, this could be very important.