USING SHEAR ULTRASONIC WAVE TRANSDUCERS TO STUDY SOFT CHEESE

摘要

Nowadays, non-destructive testing is being used to assess the quality of many foods. Noninvasive ultrasound provides a non-destructive method for determining physical properties in a wide range of them (vegetables, fruits, meats, oils, dairy, etc.). The aim of this work is to describe and show some results obtained in the non-invasive ultrasonic method to study the change in mechanical properties of organic cheese (P. O.D. Torta del Casar) made from the milk of sheep. Specifically, we show those related to the use of shear wave transducers in the test of the pieces of cheese. The results show that this type of transducer is perfectly valid to evaluate simultaneously the values of the ultrasound propagation velocities of the longitudinal and shear waves. This is because the emitted shear waves undergo a mode conversion at their incidence on the crust, with a partial transformation into longitudinal waves.