In this present work, our objective is to characterize UHT milk quality inside his package without any destruction. We propose to employ the ultrasonic transmission method which is suitable for characterization of opaque media like UHT milk. For this we follow the evolution of ultrasonic parameters in different temperatures depending on air intrusion inside package. We analyzed the experimental results between both cases: package with air intrusion and package without air intrusion. We proceed by this comparative study in order to investigate the suitability, feasibility and reliability of this emerging technique as a new alternative to the conventional destructive techniques.