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.