Work under development at LRF won the third place in the national final of the contest “IDEAS FOR MILK” promoted by EMBRAPA. The project is the result of more than six years of research, involving undergraduate and graduate students. Initially, the focus was on the petroleum extraction sites, where the knowledge of the water-oil fraction during the oil extraction carried relevant information about the well. A microwave resonant cavity based sensor has been used in this context. More recently, the group started looking for new applications for the sensor, in particular those where there is a correlation between the electrical permittivity and a property of interest. This is the case of milk, where the total of solids (mainly fat) defines the quality of the product and is submitted to specific regulations. Fortunately, we can correlate the amount of total solids (or fat) with the electrical permittivity of the milk using our microwave sensor. For the contest, we proposed to use it to improve the accuracy of the milk production process in real time. The research is conducted by prof. Fernando Rangel and prof. Daniel Pagano, by the PhD students Heron Ávila e Roddy Romero and by the undergraduate student Celso Leite.