Determination of solids and fat contents in bovine milk using a phase-locked resonant cavity sensor

Monitoring the milk quality is of fundamental importance in the food industry since milk is one of the most common product in a daily diet. The control of milk composition and detection of adulteration in raw materials are crucial in order to assure the quality of dairy based products. Different technologies for the monitoring of milk constituents in substitution of chemical processes have been reported. Recent studies showed that microwave sensors have a good potential for measuring the milk moisture content. Here, we proposed a measurement system using a resonant cavity sensor for the determination of total solids and fat contents. Its main advantages comprises non-invasive and non-destructive characteristics and fast response. Additionally, the geometry of the cavity is adapted for easy deployment in industrial facilities. We used nine characterized milk samples in order to demonstrate the feasibility of the system. The results showed a good correlation between the system response and the volume fractions of total solids and fat constituents, proving that the system is a useful platform for the analysis of milk quality.