Testing of reliability of non-destructive pressure differential package leakage testers with semi-rigid aseptic cups

The sensitivity and reliability of two commercial non-destructive leak testers were studied using commercially manufactured semi-rigid aseptic cups with headspace filled with milk pudding. The lids of some of the aseptic cups had artificially constructed holes 10–60 μm in diameter. Leak testing was based either on detection or external vacuum decay in a test chamber or internal pressure decay in the package during mechanical compression. The effect of leak testing itself on the cup integrity was also examined. From the evaluated methods, the external vacuum decay method showed greater sensitivity and reliability for detection of leakages. External vacuum and internal pressure decay methods did not reliably detect holes of 29 and 60 μm in diameter, respectively. Furthermore, neither of the methods could reliably detect the threshold leakage of 10 μm in diameter for bacterial penetration (determined earlier using aseptic cups with artificially made holes). Blocking of the holes with pudding greatly decreased the sensitivity of both leak testers. Leak testing did not affect the integrity of intact cups