A food company designed a new package for one of its product lines. The package was made of good barrier material, also the interior of the package was filled with MAP (Modified Atmosphere) gases. The product was expected to have a 6-month shelf life. However, some product started losing quality in less than a month. What’s happened here?
Surprisingly, it was found that some “bad” products are packed with some bad packages that had tiny pinholes. Sometimes people thought the pinholes were so tiny that they wouldn’t cause too big a problem. This is because it was hard to imagine how fast air could get into tiny holes, even when the hole size is as small and thin as a human hair.
In the following experiment, we will demonstrate how fast the small hole could ruin your MAP products by allowing ambient air ingress into the package.
HOW FAST ROOM AIR CAN INGRESS VIA SMALL HOLES
To focus on the hole as the only path for the O2 ingress, a non-permeable glass jar (260ml headspace) was selected for the study. Nitrogen was introduced to mimic a MAP processed package.
Then, the Leak Simulation Kit (with standard 100um and 250um holes) was used to mimic a leak path for O2 ingress.
During the test, the MOCON OpTech Model P headspace analyzer was monitoring and recording the O2 headspace change over time. As a baseline check, the original Mason jar (without the simulation hole) was also tested with OpTech to exclude other leak sources.
1. Results with 100um Hole
In fewer than 10 days, the O2% inside the glass jar is 21%, the same as the ambient. See O2 ingress profile over time (Fig. 1) below
2. Results with 250um Hole
When there is a 250um hole present, the headspace became the same as environment in fewer than 6 days. See O2 ingress profile over time (Fig. 2) below.
The above two experiments demonstrated how fast the ambient air, via tiny holes, could get into a sealed package. Until you see the above graph, most people may not believe this could happen so fast.
Leaks can come from different sources, such as pinholes on package surface, channel leaks on seals/seams, gussets, induction seals, etc. When converting flat materials into a package, the material’s barrier quality will lessen due to defects caused by the manufacturing process.
Further packing, sealing, shipping or distribution could also create defects, no matter how good the barrier material is and how well the package was flushed with MAP gas. The small hole in your package can expose your product to ambient air faster than you thought as if there is no packaging protection at all.
If you want your products to maintain good quality throughout its desired shelf life, make sure that you not only use the proper packaging barrier materials and apply correct MAP gas mixtures, but also check whether there is any leak in the package.
• When there is a small hole presenting on your packaging system, the interior headspace became the same as ambient environment in time less than you expected.
• When conducting shelf life studies on MAP packaging system, it’s important to monitor the O2% of interior headspace with a proper headspace analyzer.
• To ensure your MAP packaging is leak-free, use a proper leak Detection analyzer to test your sealed packages, online or off-line.