Food containers that change colour may soon make 'sell-by' date obsolete

Washington

EVEN in 2017, we often decide whether the salmon in our refrigerator is still edible by giving it a sniff and looking at the "sell-by" date.

A company called Braskem wants to bring a little more science into the decision.

It has developed a way to make plastic food or beverage containers change from one colour to another when they react to the changing pH levels of their contents, a sign that certain products may be spoiling. Even though this type of technology has existed in some form for decades, Braskem has certain advantages. The US$7 billion plastics-and-chemical company is the largest producer in the Americas of materials that are moulded into bottle caps, jugs, reusable containers, cosmetic packaging and much more. It has production plants in Br…