Toward the direct and online detection of freshness and health-threatening additives in milk

This paper describes a novel dielectric spectroscopic technique to investigate the milk freshness and adulterated agents using a customized, open-ended, coaxial probe. An inversely proportional relationship was found between temperature and shelf-life and the real part of the complex permittivity (ε’) of the samples at 0.1–3 GHz. At 2 GHz, a linear relationship was found in ε’ and ε”, storage time, and water content. In addition, total of five adulterants’ agents were investigated and a linear relationship was found between both ε’ and ε” parts, and their concentrations (R2 > 0.99). This approach could be the potential basis of rapid online milk quality monitoring in milk production facilities.