Leakage analysis of packages by the electrolytic test

The microhole tester is a new laboratory instrument for detection of leakage in packages. The instrument is based on electrolytic conductance measurement using direct current and it quantifies the summarized hole size in a package. In this study the reliability and validity of the microhole tester have been evaluated by testing different kinds of aseptic, retorted and gas flushed packages containing both solid and viscous products. In the case of gas flushed packages filled with a solid food product the instrument detected 100% of the leaking packages with artificially made microholes with diameters of 7–356 μm after emptying the packages of food. Retorting tended to block the holes with food and lowered the sensitivity. In the case of retorted packages with viscous food the microhole tester reliably detected hole sizes larger than 25 μm. Adding a surface active agent, poly(ethylene oxide) (PEO), to the retorted packages with totally blocked holes greatly improved the reliability of the instrument and reduced the testing time. The percentage of detected packages with totally blocked microholes with diameters between 30 and 60 μm was improved from 10–55% without PEO to 83–100% with PEO added to the package. © 1997 John Wiley & Sons, Ltd.