Fresh Onions? New Packaging Technique Can Help Vegetables Stay Fresher Longer

Vegetables, Quality, Safety

A team at Michigan State University School of Packaging—a school that is internationally known as a leader in food packaging, shelf life and product/package compatibility—has discovered new advances in packaging that can help produce stay fresher for longer.

The team looked specifically at the packaging of ready-to-use onions—one of the most commonly sold veggies worldwide.  Unfortunately onions have a relatively short shelf life. After packaging they can become more translucent, lose flavor and nutrients and go soft.  Even worse, as the onions decompose, pathogens (i.e. salmonella) can potentially lead to serious infections.

The team’s new packaging techniques can improve the quality and freshness of the onion. According to the team, sanitizing veggies and controlling a package’s atmosphere isn’t exactly a new method—so they set out to analyze an extensive assessment of techniques that hasn’t been done before.

One premium method involved packaging that maintained an atmosphere of reduced oxygen and elevated carbon dioxide. When scientists combined this with a sanitizing treatment (a bleaching agent known as sodium hypochlorite)—they came up with a sanitizer-package combo that led to diced onions being suitable for consumption after two weeks of storage.

This method also reduced onion discoloration, respiration, and microbial growth, as well as preserved the aroma. This technique could presumably provide insight into improved packaging methods for other produce.

Results are published in a recent issue of the International Journal of Food Microbiology.

Produce and Food Safety: High Pressure Technique to Kill Food Germs

More on food safety:  Previous research published in the journal Applied and Environmental Microbiology revealed how high pressure treatments—researchers in this case focused specifically on treating green onions—can kill off two major sources of food poisoning: Salmonella enterica and E. coli. High pressure treatments can preserve the gustatory attributes of the produce in question, unlike treatments that involve heating.

Many foods are  treated with heat to remove bacteria; high pressure processing treatments provide the same goal, but won’t alter the taste or color of the produce.

“New packaging advances prolongs veggie freshness,”, May 16, 2016;
“High pressure kills pathogens, maintains green onions’ taste and color,”, March 20, 2012;
H. Neetoo, et al., “Use of high hydrostatic pressure to inactivate Escherichia coli 0157:H7 and Salmonella enterica internalized within and adhered to preharvest contaminated green onions,” Applied and Environmental Microbiology, 78:2063-2065.