It's now developing a new tool to do just that: A proprietary liquid solution whose color changes in direct proportion to the amount of oxygen that has entered a sealed package. "We've been working on this indicator solution for a couple of months now," says Guelph's Nina Goodrich, business development director. While other standardized testing devices accurately measure the permeability of a lidding material, or a jar sidewall, or some other discrete package component, Guelph's solution measures oxygen's ingress into a complete packaging system, says Goodrich. "Not only does it show you if oxygen is entering, it shows you where," says Goodrich. "If oxygen is coming through the closure, for example, the liquid around the closure will show the change in color." For the time being, Guelph uses a spectrophotometer to quantify the degree of color change in its indicator solution. Ultimately, however, the firm hopes to design a machine that would do it by means of some other, more user-friendly, technology. It's working with Johnson Controls (Manchester, MI) to explore how such a machine could be manufactured.
New test for oxygen ingression
As one of the more active research centers concentrating on packaging applications for PEN, Guelph Food Technology Centre (Guelph, Ontario, Canada) has to be able to pinpoint the precise amount of oxygen that various foods will be exposed to in a given package.