RELIABILITY OF NONDESTRUCTIVE PRESSURE DIFFERENTIAL LEAKAGE TESTERS USING SEMIRIGID RETORT TRAYS

The sensitivity and reliability of two commercial nondestructive leak testers were studied using commercially manufactured semirigid retort trays with headspace filled with spaghetti in meat sauce. Leak testing was based either on detection of rise of pressure in a test chamber o r on fall of pressure in the package during mechanical compression. Ev aluated test variables included package leakage (holes of 15 to 60 mu m in diameter), retorting test pressure and pressurizing tool. The inc reased pressure differential increased the sensitivity of the method d etecting external rise of pressure in particular, whereas blockage of the holes during retorting decreased the capability of the evaluated t echniques to detect leakages. Neither of the test methods could detect threshold leakage of 10 mu m in diameter for bacterial penetration de termined earlier with similar retort trays. The leakage detection limi ts for the methods detecting external rise of pressure and the interna l fall of pressure were leakages larger than 32 mu m and 59 mu m in di ameter, respectively. Leak testing did not affect the integrity of int act packages.