Packaging to keep produce fresher for longer

Globally, onions are one of the highest volume vegetables sold, with ready-to-use onions one of the five most commonly sold vegetables in the last decade.

But pre-prepared onions have short shelf lives. They turn brown and mushy and develop a nasty odour.

At Michigan State University’s School of Packaging, Eva Almenar decided to focus on improving the shelf life of pre-prepared onions. Her team has uncovered a package and sanitiser combination that ensures diced onions are satisfactory for purchase after two weeks of storage.

Neither sanitising produce nor modified atmosphere packaging are new ideas in produce packaging. The trick lies in ascertaining the optimum combination of sanitiser and package atmosphere.

The MSU researchers found that for diced onions the atmosphere in the best packages contained elevated carbon dioxide and reduced oxygen. Combining this with sodium hypochlorite sanitising the onions could endure two weeks in a package yet still satisfy a panel of trained consumers.

This technique won’t solely benefit onions, either. It will provide insights into other packaging advances for many vegetables, she added.

Already, Almenar and MSU are conducting research on gas composition packaging and containers made from renewable resources and others from egg whites and whey protein isolate, by-products from the egg and cheese food industry, respectively.

Image credit: Eva Almenar with MSU's School of Packaging has discovered new advances in packaging that can help produce stay fresh longer. Courtesy of MSU.