An ugly truth: Store shelves often contain products that have passed their expiration date. Visit any store in any location and start reading labels - odds are, you'll find things quickly that should have been sold or tossed a long time ago.
The reason for this is pretty simple - it's sort of hard to keep track of when things expire. Store clerks are often no more likely than anyone else to be able to interpret labels, and the labels themselves are often cryptic, blurry, and otherwise difficult to read. It's simply unreasonable to assume that a consumer or someone who stocks shelves for a living can always read an inky smudge, calculate the time from that day until the date on the label, tell the difference between a "best before" date and an "expiration date," and make an informed decision.
When a retailer messes up a shelf-life label on a bag of lettuce, the result is usually nothing more than a disappointed customer eating wilted greens. Mess up the expiration date on, say, a package of pork, and it's a different situation.
Retailers are anxious to reduce the risks from expired products if for no other reason than to reduce the legal risks of selling what can make people sick. Retail chain CVS, for example, found itself facing lawsuits over the sale of expired foods and medicines. As part of a settlement with regulators, CVS promised to implement a system in which checkout registers could detect expired dairy products, baby food, infant formula, and children's medicines and notify the cashier.
Still, researchers are working on expiration labels that promise to be even more remarkable - performing tests for bacteria, monitoring time from farm to table, etc. Here's a look at three of the more interesting approaches under development:
Labels that detect pathogens
Researchers at the University of Alberta in Canada are working to create a "smart label" that can test meat and other perishables for microbes.
The idea is to create a stimulus-responsive polymer (something that changes color when certain criteria are met) that can determine when it is near E. coli, salmonella, or listeria. If something nasty begins to grow in a hamburger package, the label would change color.
For food-safety experts, the advantage of such labels is twofold. Not only could the labels provide a "warning" before someone eats contaminated food, but the smart labels would travel with the food throughout the entire production cycle. That would make it much easier to detect where and when contamination occurred.
Labels that are time-sensitive
Insignia Technologies, based in Scotland, has invented a color-changing label that the company says can help reduce food waste.
The idea is a simple one: large labels are placed on boxes and pallets of fresh produce. As time passes, the labels themselves change color. The labels themselves act as a countdown clock, letting everyone who handles the box know how much time is left before the food begins to spoil. Transportation/logistics companies, wholesalers, and retailers can tell what must be moved quickly and what should be tossed.
Labels that 'spoil'
A designer in London has developed a label that "goes bad" the same way food does. Solveiga Pakštaitė is seeking a patent for what she calls the Bump Mark.
The idea is to affix a gelatin-filled label to packages of meat. Gelatin, of course, is also an animal-based protein, so it decays at roughly the same rate as meat.
Consumers would rub their finger across the label. If it's smooth, all is well. If it feels bumpy, it's because the gelatin has begun to liquefy, and that would happen at about the same time the meat started to go bad.