Ultrasonic food quality analyzer based on cylindrical standing waves

An innovative technology based on the use of ultrasonic cylindrical standing waves for continuous monitoring of quality of various liquid food products, such as milk, juice, beer, wine, and drinking water, is described. A proprietary unique feature of the developed ultrasonic analyzer is that it employs a combined mode of operation using both highintensity (5 W/cm2) waves for separation and concentration of the large particles (fat globules, bacteria, or yeasts) and low-intensity (0.5 W/cm2) waves for compositional analysis. High accuracy for sound velocity (> 0.001%) and sound absorption (~0.5%) measurements and rapid testing time (5-20s) have been achieved. Comparative analyses of the ultrasonic method with standard reference techniques have produced linear calibration curves for major components, with correlation coefficients higher than 0.95. It is thus possible to monitor total protein and fat content, and somatic cell count in raw milk in cowsheds, or salinity, turbidity, specific gravity, and particles (bacteria) in drinking water directly. Advantages of the proposed technology include its reagent-free nature, no need for sample pretreatment, ease-of-use, and low cost.